The 17-year-old has established a reputation as one of the Gunners' most exciting youth prospects over recent years and demonstrated his significant first-team potential over the summer with a few eye-catching displays during the club's pre-season tour of Australia and China.
Sufficiently impressed, Arsene Wenger handed Nelson his senior debut in the Community Shield victory over Chelsea and also fielded the teenage prospect as a wing-back in Europa League ties against Cologne, BATE Borisov and Red Star Belgrade in addition to Carabao Cup wins over Doncaster Rovers and Norwich City.
The pacey England Under-19 international, who signed his first professional contract in December 2016, is likely to play a prominent role again on Thursday evening (2 November) as Arsenal welcome Serbia's former European Cup winners Red Star to the Emirates Stadium for the return fixture in Group H.
However, it seems he could potentially have been looking to break into Tottenham's first-team setup under Mauricio Pochettino right about now were it not for a crucial intervention when he was just nine years old.
"I used to play for a team in Catford, I would get up in the morning with my brother and get on the train and travel to Catford three times a week to play there," Nelson told the Arsenal Weekly Podcast of his formative years in south London.
"I was there for about two months playing for a team called Moonshot and then I got scouted for Tottenham. I was at Tottenham for three or four weeks I would say and then a phone call from Arsenal came.
"I went to Arsenal's training ground and in the first session they wanted to sign me so, happy days, and I didn't look back."
The future is evidently very bright indeed for Nelson, who was only promoted to the Under-23 setup in 2016-17 after shining for the Under-18s.
Wenger, who has also given the likes of Eddie Nketiah, Joe Willock and Ainsley Maitland-Niles the chance to make their mark in the cup competitions of late, is evidently a massive fan of his versatility and previously stated that the late £35m ($46.4m) summer sale of Alex Oxlade-Chamberlain to Liverpool opened the door for further senior opportunities.
"Reiss can be one of the three strikers, he can be a wing-back," Wenger said in September. "The only thing you could say is that he's more of an offensive-minded player than a defensive-minded player, but he has to learn that part of the job as well.
"He has a good engine and he's a good dribbler as well, he can pass people, unbalance defences, open defences. Overall, I believe he has a good spirit and always wants to learn. That's one of the possibilities for him. The fact that Chamberlain left opens a little door for him."