color match the nosing and the floor with correct stain color
Good news you can always stain darker over a lighter stain, but if the wood is different than the floor, it may be a little trickier. On top of that mass produced items are stained differently than on site wood typically is. You may need to use a dye and not a stain. A dye colors all the wood, and stain soaks into the softer wood and when wiped the softer wood changes more than the harder wood. You may be able to tone the finish, but that weakens the film of protection that the clear coat gives.