The 24-year-old had not scored a competitive goal in over 10 hours before breaking the deadlock as the Gunners began their quest for the Premier League title with a narrow 2-1 win.
After a 30-minute delay to kick-off following an issue at the turnstiles, Nketiah struck just after the midway point of the first-half, his deflected strike coming on the back of a fine piece of skill from Gabriel Martinelli.
Bukayo Saka’s fine curling effort proved enough to secure the points, even though Forest rallied and pulled a late goal back through substitute Taiwo Awoniyi.
“I’m delighted for him because he is a role model,” Arteta said of Nketiah, who was back in the starting XI having missed out on a berth against Manchester City in the Community Shield win last week.
“He was a player who was so disappointed not to play the final in the absence of Gabi (Jesus).
“What he did was he came on the field in the final and changed the game. That’s number one. The second one was the way he was training this week was saying ‘gaffer, if you’re not playing me you are blind’.
“A lot of players come and say ‘oh why am I not playing’ and you have to try to explain, other players come and say ‘these are the reasons why I deserve to play’. This is exactly what Eddie does.
“This is exactly what he did and then he got on the pitch and he performs that way. He’s a clear and very good example to everybody.”
Defeat at Forest in May saw Arsenal’s title charge come to an end last season and, despite starting the new campaign with a win, Arteta conceded he was concerned by the fall in performance levels.
“For sure,” he replied when asked if he was worried by the drop-off.
“It’s going to be very difficult to dominate games for 100 minutes. But we allowed them to get some grip of the game because they didn’t create anything but on that action the game changes.
“Momentum shifts immediately after that goal. That’s not the moment to change it, you cannot change it, now you have to be so good at dealing with that situation, running the clock down and earning the points.
“The team has done that really well but we’re going to have to be more ruthless and more critical of ourselves to be more pushy and kill the game.”
Forest boss Steve Cooper was left ruing the defending for Arsenal’s goals after setting up the visitors to create the sort of chances that led to their late consolation.
“I was disappointed with elements of our game in the first half,” he said.
“Structurally we were good but I didn’t like us on the goals – we should have defended those much better.
“I didn’t love that we didn’t back ourselves in the duels. I showed some clips to the lads at half time – we needed to believe, back ourselves and compete.
“The real chance in the first half was Brennan Johnson’s from open play. The plan was going to plan with our counter-attacks but we needed to compete more. So it is a game of ‘what might have been’.”