First things first.
So glad you joined our growing family of Yorkie lovers.
There are dozens of high quality foods on the market. The best answer I can give is the best food for your baby is the one that works best for him. You may have to do some trial and error. My girls don't tolerate chickpeas (aka garbanzo beans) or a lot of chicken. Sometimes dog food producers change formulas, so I always read the ingredient labels.