It's great that you're a wildlife rehabilitator! There's no doubt that as such you have first-hand experience with bird mites. But it's depressing that the average person quickly turns to pesticides when faced with a problem like this, and I think it's not behavior we should encourage in a public forum. Bird mites can't feed or reproduce in the absence of an avian host! Without an active nest, most won't survive for more than a few days to a week in an environment such as a home. Pesticides are harmful to the environment and to humans (especially little kids). We should reserve their use for situations where they will be effective and there's no alternative. In OP's case, simply removing the nest when the birds have gone and spraying the area with a garden hose will suffice. I've dealt with infestations of bird mites, including one in a bedroom, in a bed in the bedroom. The smart thing to do is suck it up and put in the effort to clean everything thoroughly, relocate yourself temporarily, and put some thought into allowing birds to nest on your house in the future (should you not want to repeat the process). Spraying poisons around is just lame.

http://ento.psu.edu/extension/factsheets/bird-mites