Anyone can be sued for any reason. It is extremely unlikely a suit against Twitter for moderation will succeed. In theory they have the legal ability to remove all GOP politicians, knitters, or fast food companies from their platform.
The newest Executive Order about Section 230 means the FTC can enforce anytime Twitter doesn’t follow their own stated policies. So Twitter will just adjust their policies to give themselves more latitude. Even this is legally murky and will take years to be resolved in court.