The three-time world champion, chasing a record-extending sixth title at the event, found himself repeatedly on the ropes against the 24-year-old, who led 2-0, 3-1 and 5-4.
Nijman missed a match dart in the penultimate leg before Van Gerwen struck back, sealing victory with a 104.75 average and a clinical double 18 after a sublime 174 set-up shot.
“I am delighted with this result,” said Van Gerwen, who lifted the title in 2015, 2016, 2017, 2019 and 2023.
“Wessel is a great player, and his cover shooting was phenomenal tonight, but I felt great the whole game.
“I think this was one of my best performances in Holland for a long time, and that gives me a lot of joy.”
Van Gerwen will face Rob Cross in round two after the 2018 world champion held off New Zealand’s Haupai Puha 6-3, landing 60% of his doubles in a strong opening display.
Elsewhere on the opening night, Luke Humphries also survived match darts, beating James Wade 6-5 in a nervy contest.
“It was a strange performance,” said the world No. 1, who produced legs of 14 and 13 darts to overturn a 5-4 deficit.
“One minute it was great, the next really poor. My consistency is not there yet, but I’m working my way back into form, and I’m pleased to win.
“I was very fortunate James missed those two match darts, but when I get past that first round, I’m usually dangerous, and now I’m hungrier than ever.”
There was disappointment for Stephen Bunting, who fell 6-4 to Dutch No. 2 Danny Noppert.
Noppert’s reward is a clash with World Cup winner Josh Rock, who defeated Krzysztof Ratajski 6-3, finishing with a 121 checkout on the bull.
Australia’s Damon Heta produced a dominant 6-1 win over Joe Cullen, while Mike De Decker overcame Gabriel Clemens 6-3.
Kevin Doets also advanced, defeating compatriot Jermaine Wattimena despite surviving four match darts.
Saturday’s afternoon session will see defending champion Luke Littler begin his campaign against Simon Whitlock.
Gerwyn Price and Jonny Clayton meet American opposition in Danny Lauby and Jason Brandon, respectively, while Raymond van Barneveld faces Norway’s Cor Dekker.
Nathan Aspinall, Chris Dobey, Ross Smith, Peter Wright and Cameron Menzies also enter the fray.
The second round follows on Saturday evening, before Sunday’s quarter-finals, semi-finals and final.
Click here for match stats and more.
Results
Kevin Doets 6-5 Jermaine Wattimena
Josh Rock 6-3 Krzysztof Ratajski
Damon Heta 6-1 Joe Cullen
Mike De Decker 6-3 Gabriel Clemens
Luke Humphries 6-5 James Wade
Michael van Gerwen 6-5 Wessel Nijman
Danny Noppert 6-4 Stephen Bunting
Rob Cross 6-3 Haupai Puha