What is the best sun screen to use after MOHS on the nose?

Physical sunscreens are an excellent choice ideally with SPF 30 or greater. There are chemical sunscreens that work but I prefer micronized zinc oxide as a block.

The simple answer is to use the sunscreen and sun-protective measures that you like to use. If you don't like using it, you won't use it as often as you should. That being said... The sunscreen should have an SPF of 30 or higher. Studies have shown that most people apply about half as much sunscreen as is necessary to get the SPF listed on the bottle so apply it liberally. And apply it frequently...apply every 3-4 hours that you're outside, more often if swimming or sweating or toweling off.  It should screen out UVA as well as UVB (i.e. should say broad spectrum). And waterproof is not a bad option because it will probably last longer on your skin. There are a lot of good options out there including Neutrogena, SolBar, etc. You might talk to your dermatologist and see what he/she recommends. Remember, you should continue to follow up with your dermatologist to make sure that you don't get any more skin cancers or that the ones that have been treated don't recur. With hats the wider the brim the better, especially if the brim wraps around (i.e. not just a ball cap). However, if you're not going to wear it, it won't do you any good. So a broad-brimmed (i.e. 3-4 inches) wraparound hat would be best, but at least get in the habit of wearing a ball cap to offer some protection. And even if you're wearing a hat, put on the sunscreen. Good luck.