I found no indications that 0fficials have approved any nicotine treatments for COVID. 

 But there were some statistical reviews that smokers had some lesser effects from COVID in 2020, earlier in the pandemic, by Israel & other groups

There were some references that studies were being started or planned in 2020 by French, and British groups.  These would involve the using nicotine in products designed to help break the smoking habit-- like nicotine patches, & nicotine gum.  Side effects were mentioned from the patches such as burning irritation can result from those patches. 

The hopes were that so call "long COVID" cases might be helped.  Yet I saw no summaries of the results of those studies nor conclusions, nor recommended treatments.   

BUT Smoking is NOT recommended, and there's been plenty of health warnings against that idea. In 2022 the medical journal Lancet said:  " given the devastating health effects of smoking, and the deep-pocketed tobacco industry's efforts to downplay the dangers of smoking, 4 authors—especially during a global public health crisis—must exercise great caution when speculating about beneficial effects of smoking, as they should also do for non-randomized, uncontrolled efficacy studies."  Click Here  

Another a skeptical report has said that the nicotine benefits appeared weak.     Click Here   

Isolated reports have suggested the nicotine patches "MAY" help or with qualifiers like "hospitalized patients".  BUT again, I found no indications that 0fficials have approved any nicotine treatments for COVID.  

PS Medical guidance is recommended before trying those nicotine patches, just as was provided  in the French & British (Welsh) studies