[Maximo]

American cheese has a lot of fat in it and can put Yorkies at risk for pancreatitis. I would hold the cheese, or substitute fresh parmesan which is lower fat. Powdered grated parmesan is usually loaded with salt. But if he continues to have tummy problems, discontinue all cheese.

Lunch meats also have a lot of salt, so good to discontinue that. One thing that Wylie's Mom often mentions is gerd, acid reflux, related to tummy problems. Salt can be a contributing factor.

Nutro is a controversial brand. You can google some of the complaints about the manufacturer. My oldest boy ate it when he was a pup and didn't have problems, but we switched brands.

Next time you are at the vet with a tummy problem, definitely discuss diet.