After my husband died, I drastically reduced the amount of time his parents get to see my kids.
Is that a good idea? Why don't you want them to spend time with your kids?
They are nosy about my family.
While it is sad for them not to have a relationship with their grandparents, as a parent you need to do your best by them. Removing toxic relationships from their life is good.
Everyone else thinks my actions are wrong and I should talk about it with them.
If you haven't tried talking to his parents yet, I think you should take everyone's advice and do that. Not letting them see their grandkids is rather harsh if you haven't even tried to talk to them about their problematic behavior. Explain how you feel and they will probably be willing to be less nosy.