Short answer: A cat will eat bugs and birds if given an opportunity, after all!
Buy some "Temptations" at your local supermarket. I've yet to meet a cat that doesn't love them.
As for nutrition, I've yet to meet a cat made sickly by store-bought food. If anything, most house pets are over-fed/overweight.
That said, we do buy more expensive than normal cat food -- hairball control Science Diet -- due to having spent more money than we care to recount on two emergency surgeries for one of our cats due to intestinal obstructions. We didn't switch to it until we and our cat had gone through its second emergency surgery. That makes sense to me, given the ordeal we've gone through and the evidence we have that this food helps intestinal obstruction prone cats eliminate hair properly.
PS: Pet stores don't have some lock on what's good for pets, by the way. If you're really concerned, talk to a licensed veterinarian -- preferably the one seeing your pets, so they can be evaluated for any unique issues they might have.