What would you do? Cat vomiting

Thanks, I'll see if my vet has it.

Wet foods such as Hill's A/D and Royal Canin's Recovery RS ( especially the Recovery) have been found acceptable by our shelter cats who won't touch anything else...

See if you can get those from your vet. Again, I suggest seeing another vet for a second opinion.

Canned chicken is like canned tuna.. okay as an occasional treat but NOT good as a regular diet for a cat. It does not contain the nutrients that cats absolutely require for good health.