We have the same problem, with cherry-stained interior. Not only a small nick or two, but also some areas near the floor where the color has worn off.
Here is your solution. These can be found at Lowe's, Menard's, Ace Hardware, etc. You can use a bit of wood filler first, if you need to.
They come in several stain shades. We have the cherry for the Interstate, and antique oak for the molding at home.
They work beautifully
, trust me. We are a bit persnickety, like to keep things looking nice.
Once the stain touch-up has dried thoroughly, cover the area....and the rest of the wood finish....with a good wood polish and conditioner. We have one by Howard, with orange oil and beeswax in it. Protects your finish and makes everything look lovely.