Graham, a former Linfield attacker, has been an unused substitute in three fixtures for Everton this season. Despite his own club's shortage of options at number nine, Toffees boss David Moyes said this month he believes the 18-year-old is "probably someone who would play off the sides" in the Premier League, rather than through the middle.
O'Neill has included Graham in his squad for a Uefa Nations League quadruple-header that begins away to Georgia on 25 September, and feels the teenager's versatility should be embraced rather than narrowed.
"I think the most important thing is not to try and pigeonhole him into a position," O'Neill said. "He's adaptable and he's adaptable because he's such a good player. I think at this minute in time his best option would be to play a little bit off the side, possibly as a 10, maybe around a bigger striker if you play a front-two, which not many teams do.
"What he has shown us in training is a real high technical level and the ability to stick the ball in the net."
This is Graham's second call-up to the senior Northern Ireland squad, having previously featured in June's panel for friendlies against Guinea and France. He was preparing to come on against France when the final whistle went before he could make his senior debut, though O'Neill felt the forward had "deserved" a first cap based on how he had trained throughout that camp.
On the question of Graham's long-term position, standing at 5ft 9in, O'Neill stressed that physical development varies significantly between players.
"I've watched him a lot, we've watched Braiden since he was young, I've seen him from like 14 or 15," he said. "Every player develops physically differently. It's very difficult to play in the Premier League as a striker, look at the profile of what clubs want as their striker.
"But Braiden's a very talented player, he's a very technical player, a great finisher. He has a really good left foot, he's smart in terms of how he plays."