Every odor specialist I have ever talked to said the only fairly sure thing
is to seal it in. Get it as clean as you can and then use a sealer-
polyurethane should work.
I don't know what nature's miracle is, but vinegar or sudsy ammonia clean
pretty well.
good luck.
We almost bought a house that had been a kennel for a couple of months, with
no humans around, so we had a specialist from 200 mi away come to assess and
recommend.
Armand