When December 15th hits, almost every player in the NBA will be eligible to be traded, including players signed in the offseason. For the Nuggets, that means Bruce Brown and Tim Hardaway Jr. will become eligible on the 15th, and Denver can include them in any deal between then and the trade deadline, should they choose to do so.
Of course, most of the rest of the players on the roster have been trade eligible, and that will continue to be the case. Christian Braun was extended, so he won’t be dealt, and nobody is expecting the Nuggets to move any of their Big 3 of Nikola Jokic, Jamal Murray, and Aaron Gordon.