A quick warning that engineering works will hinder anyone travelling to Forest’s home game with Leeds on New Year’s Day.
Trains from London St Pancras International will terminate at Bedford where “an express rail replacement coach service” will run between Bedford and Corby. From Corby you can then connect with trains to Nottingham. Journey times will be around three hours. A copy of East Midlands Trains’ New Year’s Day timetable is available here
If a bus isn’t your thing you can of course, travel via Grantham on LNER routes, but expect to pay something in excess of £50 for the privilege.