With the Mavs loss to the Warriors tonight, they fall into a three-way tie with the Nuggets and Warriors at 45-28. But, since the Mavs have lost the season series to the Nuggets 2-1 and Denver currently holds the season series lead over Golden State 2-1, Denver gets to be the 7 seed...for now.
The Mavs get to be the 8 seed out of all this because they still hold the season series lead over the Warriors 2-1. Don't get too excited, though, the Mavs will face Golden State in two games in Dallas next Wednesday. That game will be humongous since this playoff stretch could come down to tied records on the last day, and a tiebreaker over the Warriors is as important to them as potentially gaining a game on them.
The Warriors play at San Antonio on Tuesday for their next game, and Denver plays their next game at Phoenix tomorrow.