Not NATO necessarily, but trade blockades on Russian ports accessible through European waters, hard sanctions, actual seizing of Russian assets, and potentially coalition troops from various countries with approval from Ukraine. NATO isn’t an offensive pact, only defensive. However those countries could form coalition forces to strike back at Russian military assets in Crimea. Instead we just lightly slapped them on the wrist and said “don’t do that again” and then they straight up murdered civilians and attacked a non-aggressive border nation.