Painting and a tenant that smokes

[Kenneth Sok]

I have an inherited tenant from a property I purchased from a tired landlord.

The tenant is great: pays on time, takes care of his own maintenance, also agreed to pay higher rents to match market prices, etc. 

He's a smoker though and the whole place reeks and has stains from his 20+ years living there.

I would like to keep him in the property for as long as possible. I want to refinance the house with a long-term lender and need a good appraisal. To get a higher appraisal amount, I would like to repaint the house in order to make the house cleaner.

Is there a solution that would fix the smoke/nicotine stained walls and keep it from being stained again? Or should I just paint over it with a cheaper paint for the appraisal and then get a more permanent solution when he moves out?

What kind of paint would solve the smoke and nicotine smell? I've heard of a stain-blocking latex paint. Can anyone speak to this? 

Many thanks!