Hey there! Yes, Geralt would actually get on really well with Jon! Jon's honourable, Northen and knows how to handle a sword. I'm sure they would fast become friends.

He'd probably drink Jon under the table though, but that's mostly because Geralt's DNA has been massively tampered with. Oh and he'd be impressed with Jon's sword if he has it with him? But yes! They need to meet and maybe even have a friendly horse race some time!