The teenager also made Gunners history by opening the scoring goal against Brighton in a match that ended 1-1.
Nwaneri put his side in front at the Amex after 16 minutes as he found a way past Bart Verbruggen.
His strike is his second Premier League goal for Arsenal, still two months short of his 18th birthday.
It means the 17-year-old is now the first Gunners player to score twice in the competition before the age of 18.
In doing so he has beaten both Cesc Fabregas and Bukayo Saka to the feat.
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Fabregas opened his Premier League account at 17 but had turned 18 by the time he added to his tally.
Meanwhile, Saka failed to score before his 18th birthday and was 19 by the time he grabbed another goal.
Nwaneri previously scored his first league goal for the club in the 3-0 win over Nottingham Forest in November.
His goal on Saturday also sees the midfielder become just the sixth player to score multiple Premier League goals before turning 18.
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He follows in the footsteps of Wayne Rooney (7), Michael Owen (5), Danny Cadamarteri (3), James Milner (3) and Federico Macheda (2).
Nwaneri could still add to his tally after starting consecutive games for Mikel Arteta's side.
The England under-19 international does not turn 18 until March 21.
As well as his scoring achievements, Nwaneri is already the youngest player in Premier League history.
Arteta handed the Hale End graduate his debut against Brentford aged 15 years and 181 days back in September 2022.
Nwaneri has since made a total of 20 senior appearances for the Gunners, including his start against Brighton.
Of those, 14 have come in the Premier League for his boyhood club.