Thrive wet is a complete food but it must have some additives over boiled chicken to make it complete so may not always suit.... worth a try for the long haul maybe though. Mine do not like Thrive chicken at all! Not sure why
I also feed steamed white fish for a tummy upset sometimes. A nice fillet of cod or haddock gently steamed in the microwave and mashed up. Served warm with some extra water will be lapped up by most cats. My 3-5 week old kittens were actually helping themselves to their 5-5 week old aunts and uncles cod lunch earlier
I actually poach it in Goats milk for the kittens as they can digest Goats milk easily enough but this might not be a great idea for a sickly tummy.
Complete wet foods like Highlife chicken might be bland enough for sensitive tums as well as Pets at Home Purely Chicken... especially kitten formula ones.