Nowitzki became only the sixth player in NBA history to reach the 30,000-point mark this year.
Nowitzki, who turns 39 in June, said last month he planned to honor the final two years of his contract, form and fitness permitting.
And the German ace reconfirmed that pledge on Thursday in an interview following the conclusion of the regular season.
"Definitely playing next year," Nowitzki told reporters.
Nowitzki averaged 14.2 points in 54 games this season, his lowest average since his rookie season of 1998-99 when he contributed 8.2 per game.
"If I feel like I did at the end, I think I can play another one after that," Nowitzki said, raising the prospect of playing in the 2018-2019 season.
"I will just leave all that open. When I signed on for two more years last summer, that was the plan."
Nowitzki became only the sixth player in NBA history to reach the 30,000-point mark this year when when he broke the barrier in March.
The power forward has scored 30,260 points. The Mavericks finished outside the playoff places in 11th spot this season with a 33-49 record.