There is no way to clean it unless you remove the paint that is covering it first. You could paint over everything with BIN though to seal the odors in. Just make sure none of the paint is peeling before doing that since sometimes paint doesn't like to stick to heavily stained surfaces. Also, the odors are in the floors as well, so if you are replacing carpet it's best to clean the plywood underneath and apply a coat of Kilz or BIN before installing new carpet.

My house was the same way when I moved in, I gave it the odor fogger treatment, did the BIN primer which sealed the plaster walls. Luckily I did not have carpeting, if so I would rip that out as well. Everything needs to be scrubbed down, might want to hire a cleaning company to do it.

Move out. Have the ductwork professionally cleaned. Have every single surface of the 6 sides of the cube painted with BIN or refinished. Recessed lights, replace. Electrical outlets, open and then apply foam air sealing. Examine the insulation in the attic. If there is insufficient air sealing, it will be contamination bated and need replacing as well.

And be very careful to not touch any of the walls or anything else that is contaminated without gloves. Nicotine is a poison, and it can enter the bloodstream via skin contact.

What Sophie is talking about is third hand smoke (THS). This is what you get when second hand smoke is deposited on surfaces.

I can't find a reference for this now, but I seem to recall reading decades ago that the brownish-yellowish color you see on surfaces in a heavy smoker's home is actually mostly from the tars in the smoke, not the nicotine.

Nicotine deposits are left behind too, but from what I've read more recently, they eventually dissipate. Presumably that means that they vaporize, which doesn't sound so good either.

It's not just the nicotine itself that's a concern, it's also carcinogens that result from the reaction between the nicotine and nitrous acid in interior air. These carcinogens are called tobacco specific nitrosamines (TSNAs).

The main source of indoor nitrous acid is gas ranges. A gas range with all 4 burners and its oven going is consuming 44,000 BTU/hr, more than a 50 gallon water heater! Yet it's unvented, and spews all of its products of combustion into your indoor air. (Given my choice, I wouldn't have a gas range in my house, but I'm outvoted here.)

So, if you cook with electricity, your hazard from this will be lower.

How much either the nicotine itself, or the nitrosamines, actually harms your health isn't clear to me. Many of these health impacts are cumulative, though, so less or none will always be better. In this case, as with lead, the hazards are apparently greater for children than for adults.

I expect that the bottom line in your case is that if the nasty stuff is sealed in by a couple of coats of BIN or similar sealing paint, you should be fine.