How closely did you follow that recipe?

I only ask because that recipe won’t work exactly as written and neither will most recipes you find online. The only websites I follow closely are Americas’s Test Kitchen and Serious Eats, even then, some tweaking might be involved.

This recipe lacks salt (outside of the soy sauce) and aromatics like garlic, ginger, and peanut oil.

I used to make bland stir fry until I finally figured out some things rules and they translate across cooking:

• Salt is important! Making noodles, rice, potatoes, beans, lentils, etc? Heavily salt the water. Salt meat before you cook it. Taste your dish while cooking it and add more salt if it needs it. Taste it before you serve it and add more if it needs it. Obviously, too much salt can be a problem but it’s still better than heavily processed foods.
• Sear all meat until it forms a browned layer. Look up the Malliard Reaction. It’s goes for veg too when roasting or frying.
• Fry aromatics like onions, garlic, ginger, and dried spices before adding anything else to the pot/pan.
• Taste the sauce before you use it. That sauce is okay but doesn’t seem like enough for that amount of food. Also, you’d be surprised how much sugar is in store bought and restaurant sauces. I don’t think the amount in this recipe is enough.
• Speaking of sauce, a very small amount of sesame or peanut oil can go a long way to enhancing a stir fry sauce. Worcestershire sauce also seems like a weird addition.

There isn't enough info to diagnose correctly as both the recipe and your steps were not detailed enough.

Questions that would help clarify:

1. What noodles did you get? Dried, or refrigerated fresh noodles?

2. I assume you bought dried because you said you cooked the noodles for 6 minutes like the pack said. You didn't specify what you cooked them in. If just plain water, that is likely your culprit. The noodles absorb plain water and taste, plain. Remember the Italian rule for cooking pasta, the water should be almost as salty as the sea. The pasta absorbs the water and pick up the salt making a yummy flavourful pasta.

My first recomendation is to add salt about 1% by weight and experiment a few times until you learn what tastes best to you.

My protip for any noodle in any cuisine is to replace water with a broth. A nice bone broth, chicken/pork/beef, veg broth or mushroom broth, with the right amount of salt elevates the noodle with increadible flavour. Best of all you can buy broths cheap, or make your own with scraps. My personal faves are bone and mushrooms when homemade and chicken when buying. Just remember store bought broths already have salt, so you will need to add less before cooking your noodles.

I can't speak to your noodles in a broad sense but one thing I notice with the recipe you linked is it looks like they're doing a proper wok stir fry. Wok cooking is usually at much higher temps than regular stoves reach, and gets much smokier which adds a fair bit of flavour. You can get most of the way there with a regular pan but it's not as easy.

That means your cook times in just a flat bottom pan on a regular stove are going to be different, you can't just time it you'll have to actually look for the signs things are at the right stage. You'll need to cook the sauce down more to get it thick enough to coat the noodles, you'll need to make sure the chicken is properly caramelized, and you might need to cook the veg longer before adding the chicken back.

After the initial stir fry I'd cook the chicken and veg in the sauce some (kind of braising them) before adding the noodles to help it reduce and cling. This might overly soften the veggies so you'll have to play around with timings, or take the veggies out, reduce the sauce some, then add everything. Personally I'm too lazy for that, lol.

I guess a broad comment would be just make sure you learn to look for the signs of when to move on to the next stage of a recipe, don't just time things.

I can’t load the recipe, I think my adblockers are too strong lol. But I just typed something up if that’s helpful. Like this is how a typical stir fry would go:

Cook noodles til al dente. Set aside.

Stir-frying in a deep pan or wok: (This will go fast, like 5, <10 mins, if using high heat. I personally use medium to medium-high heat bc I use a lot less oil and therefore don’t want to burn my food. Restaurants will use high oil, high heat = very fast cooking. But in any case, have everything prepped and ready to go):

Brown your protein. Add aromatics, such as garlic, ginger, chilis, etc. When that’s smelling good, add your veggies (make sure to chop in similar sizes so they cook quickly and evenly). Add salt (basics are any combination of oyster sauce, soy sauce, chicken bouillon. Add Worcestershire I suppose for yakisoba?). A pinch of sugar for balance (a splash of mirin here has the same effect). Spoon in some water, usually the pan needs to de-glaze at this point. Toss in the noodles. Taste and add more seasoning as needed (usually salt).

Usually the thing is to use the least amount of water possible when boiling noodles to keep the starches concentrated, then when you move them to the pan the starch can help bind the fat and the water to emulsify into a clingy sauce. Instead of draining them, just move them over with a slotted fork and don't worry about drip drying them.

However this recipe specifically calls for not boiling them like the packet says and merely using hot water for a minute or two to loosen them enough to finish cooking in the pan with everything. This is probably to prevent the noodles from over-cooking and becoming mushy and the noodles will probably release more starch as they finish cooking in the pan.

A hidden part of every recipe is “season to taste”

Taste the dish before you remove it from the pan.

Add whatever it needs, and taste again before plating.

Looking at the ingredients, I think it needs a dash or two of white pepper, probably garlic too.

add salt and MSG, usually fixes most of my bland tasting noodle meals.

Did you taste the chicken and veg before you put the noodles? You might have needed more sodium, from whatever source.

After cooking noodles, I'll drain them and let them sit while I make the broth perfect. Then let the noodles sit in the broth for a bit.

Bland

Did you drain the noodles first and give them some good shakes? Too much water is bad.

the noodles didnt hang on to the sauce at all somehow

This could be too much water as above, but might have other causes. Did the sauce feel like it was separate layers rather than an integrated thing?

How did you add the cornstarch? This could impact final quality.

Did you make any substitutions or alterations to the recipe or equipment?

Make sure the noodles are drained properly and not very wet when you mix them in, so the sauce sticks. Also, try adding an additional tbsp of oyster sauce. It won’t hurt and can drastically improve the umami flavor.