The big three smells from a slot....
Tobacco smoke which is topical (on the surface).
Then comes bacteria - generally from soda and similar drinks being spilt into or on the machine.
Finally Mold which comes from moisture - most likely from the drinks mixed with all of the above.
I suggest stripping your machine of everything you can, get a supersized roll of paper towels and wiping all the surfaces with Mr. Clean (or similar degreaser) this will help remove the tobacco layer.
Next I would use a spray bottle with Vinegar perhaps mixed with water. This will get into all the seams and corners that you didn't get to and its good for killing mold.
Also treat the outside of your machine as this is what was exposed to the casino environment.
Finally on the inside I would use Killz which is a restoration primer. The professionals use this on fire and water damaged homes. Covers anything that smells.
https://www.homedepot.ca/product/kilz-restoration-interior-primer-3-79-l/1000743019Its also available as a spray but depending on what you took out (or more importantly didn't take out) of your machine you may want to put it on by brush.
Just remember that your glass needs to be washed with water and only a very mild detergent, same with reel strips, all of which can easily be layerd with tobacco and stink (Both sides).