Not everyone in the car wants a burger. The Chicken & More combos cover tenders, chicken sandwiches, and the occasional fish option, all sold with fries and a drink at combo pricing.
This page walks through what's in each meal, how many tenders you get, and which sauces come with what.
Value is a bigger factor here than on the burger side of the menu, mostly because tender counts and fillet sizes are easier to compare directly than burger patty weights are. If you're choosing between two combos on price alone, checking the piece count or sandwich size first will tell you more than the listed price does.