Nicotine is a tar so I would after testing go with ultrapac or fabric restorer it's going to need a good dwell, I would brush in and towel off then hwe when you get the results you want I would then again towel off so the nicotine that is encrusted into the fabric doesn't wick through, bio clean post sprayed and towel dried may be a good way of reducing the smell.
Then go home and wash your kit, throw your clothes in the washing machine and have a good shower.
Shaun