Donaldson was twice part of an Inverness Caledonian Thistle team last term which managed to prevent the then Dunfermline Athletic striker from adding to the 23-goal haul which won him a £250,000 move to Easter Road in the summer.
Nisbet is now being tipped for international honours but the prospect of facing the in-form frontman does not faze the Dingwall defender.
Speaking ahead of the Staggies’ meeting with Hibs on Saturday, Donaldson said: "I played against him twice last year. He's a decent player and you could definitely see he was a Premiership player playing in the Championship at that stage.
"He did really well to continue his Raith form on with Dunfermline. Confidence for a striker is a huge thing and he has got an abundance of that right now.
"I'm looking forward to a tough game but also relishing the challenge.
"I'm not surprised to see him get tipped for a Scotland call-up. We've seen Steve Clarke make it clear if you do well for your club you'll get a chance.
"But I'm not worried about that at all. I spent three years in the Championship.
"Now I'm at this level I just look forward to taking on guys like your Nisbets, your Edouards and your Moreloses.
"There's no fear, I just look forward to the challenge."