I think it's important to have confidence when you do nails and teeth. Once you decide you can do them, it's funny how the yorkies "change". Humans that have to be sure of it. Use a treat on the side. Remember, a wet nail is a weaker one. A yorkie being bathed is a distracted one. Take advantage of these things. I don't like the old fashion nail clippers. They take too long to get ready to cut. I prefer a pair that look like these:
Millers Forge Designer Series Dog Nail Clipper I'm not promoting this company. You should be able to buy them for less than this price.
For the worst situation you could mummy wrap after bathing. Then pull out each hand/foot from the towel.
Regardless. They should be barley snipped with each bath. Keep some stop bleed on hand just in case. Do not fear a bloody nail. Once you get past a few you won't be as leery of it happening. IMO some yorkies have ticklish feet. Some yorkies will lay there. Just be confident and go for it.