To get an idea of nitro odor, go to a dirt bike race. Smells a lot like 100+ octane race gas.
??? Nitro doesn't smell like gas and its oder isn't as strong as gas. Last time I went to a dirt bike race they were using gas, with 2 stroke oil, some with castor oil. Now that was in the 70's and things may have changed, but since I don't see any need for extreme speed jumping hills and such, I suspect they are still using gas.