Nickle plating will resist corrosion, scratching, and surface wear better than brass, iron, or most steels. How ever, as stated above, it does nothing to add strength.
As for the question of solvents, the problem comes when using bore solvents that are supposed to remove copper fouling. Part of the surface preparation for most nickle plating involves first plating with copper. If a copper solvent gets under the nickle via some tiny defect it will attack the copper and the nickle comes free and flakes off. Such tiny defects often occur at plating edges or at the muzzle where there is usually an edge to the nickle plating and the most likely place to get wet with bore cleaner. So you want to be picky about what you use for cleaning. (Ammonia will also attack copper, it's an ingredient in some copper fouling solvents.)
