The Algeria Under-23 international is due to arrive from Greece on Tuesday to complete his move from Panionios and could even make his debut in the Scottish Communities League Cup against Dundee later in the evening.
The former Le Havre player spent last week training with the Pittodrie club and Brown believes he can help compensate for the loss of Chris Maguire to Derby.
The Aberdeen boss is confident the 22-year-old will excite the fans as he joins Scott Vernon, Josh Magennis and Darren Mackie in the Dons' strike department.
Brown said: "I genuinely think that our strikers at the moment should excite the fans.
"Vernon is an exciting player when he goes through on goal and when a cross comes in you expect Scott Vernon to be there or thereabouts.
"Josh, we all know how the fans can be lifted when he gets possession. Darren Mackie works tirelessly and is an exciting player.
"But I think Chalali is slightly different because he's more disposed to taking a man on and beat him on the ground, and does the kind of job that Maguire did here, which was mainly creation.
"But I think on the evidence we have seen of Mohamed Chalali, he'll score as well as create so we are optimistic about that signing."
Chalali is keen to play against Irn-Bru First Division side Dundee at Pittodrie, although Aberdeen are awaiting international clearance and Brown is unsure the player will be at his peak condition.
"He is in Greece and he will be back tomorrow at midday with, hopefully, the right documentation," Brown said.
"Whether, having left at 5am from Greece, he'll be fit and ready to play is another matter, although he is telling us he will go to bed when he gets here.
"I've not ruled him out because he is desperate to get into action, it will be a good boost if he's here in time.
"The clubs are agreed, we have the signatures required and we have to get international clearance from the Greek FA. That's the only missing link in the transfer."