Holt netted his first goal within 25 minutes of his debut following his £300,000 capture from Rochdale and then turned creator to send strike partner Nathan Tyson clear to make it 2-0 in the second half.
Within three minutes of his 63rd minute strike, Forest had the game dead and buried as Nicky Southall picked up the pieces to fire into an empty net after Oldham keeper Chris Day had failed to hold on to Kris Commons' rising drive.
It was Forest's 10th home win of the season and edged them closer to the play-off places.
It was Oldham who almost drew first blood as the lively Paul Edwards made progress down the left flank and provided a pin-point cross towards the near side of the six-yard box for Andy Liddell.
The striker connected well with his shot but saw the ball cannon back off defender Wes Morgan when it seemed goalbound.
Holt came close with a header in the first 10 minutes as he rose highest to attack a Commons corner but directed his effort over the crossbar.
Oldham hit back as Edwards twice again delivered teasing balls into the box but twice Oldham failed to make the vital connection.
And when Commons linked up with Holt for a second time, it lead to a goal for the debut boy with his free-kick picking out the striker again on the edge of the six-yard box from where he powered home.
After the interval it was Forest who again started with confidence with Commons and Holt both coming close with long-range efforts, while Tyson also forced a good save from Day as he struck a vicious shot from the edge of the box.
The visitors were punished for a second when, given a second opportunity of his own, Tyson put Forest two ahead after racing on to the end of Holt's pass before rifling the ball into the bottom corner of the net.
This time the wind was knocked out of Oldham's sails and within three minutes it was 3-0 as Day made a fine save to deny Commons but saw the rebound fall perfectly for Southall to lash home from close range.