The Equal Time Rule would require Kimmel to offer to air an equal-time interview to Ken Paxton as well as Talarico. Unless Kimmel's program is a bona fide news program, which would be exempt from the rule.
Previous administrations adopted a more broad interpretation of "bona fide news program" that included these late night shows that interview guests. Mainly because this rule and the exception are playing with legal fire regarding the first amendment and core political speech.
The Equal Time Rule applies only to over the air broadcasts. YouTube is unregulated on that point.