Greetings @Sage64!
I’m experimenting with an Herbal Insect Repellent recipe right now- I used mint as one of the herbs I used as I had seen it listed in several insect repellent recipes while I was gathering research. And as catnip is technically in the mint family, I think it would be fine to use in any recipe that calls for mint! 
You’ve got some awesome recipes here from everyone- I hope you can find a great one to put your catnip oil to use! 
Blessed be!