How can I refinish solid oak chairs with a maple stain?

Get some Kutzit paint remover. Spread it on thick with a brush. follow instructions on the can. You may have to put a second coat on for it to completely get everything off. Once you have removed everything, wet a rag with denatured alcohol and go over everything. If you still see some paint spots put a little more Kutzit on there and take a piece of steel wool and scrub lightly. Once removed, go over the spot with denatured alcohol. Then sand it well and wipe down with a tack cloth, this will get all the sawdust off. Then proceed with your stain. Try taking a look at the gel stains vs the minwax variety. I would stain a small piece under the table first to make sure you get the right one. Good luck with your project.

What kind of chair? is this a 1930s Comet Lounge Chair? if so it would ruin its value to refinish it. https://www.decorativecollective.com/dealers/goldwood-by-boris/p/chairs-gbb1076

Use that citrus based paint remover, and strip the layers of stuff off. Then sand and treat with pre-stain conditioner. Time consuming but tried and true!

patience, have patience and take your time striping and sanding.