The forward scored a predatory diving header - his sixth goal in three U18 Premier League North appearances this season - to ensure the young Reds emerged from an incident-packed match with a hard-earned point.
Marc Bridge-Wilkinson was forced to make two first-half substitutions due to injuries sustained by Francis Gyimah and James McConnell, who had earlier put his team in front before Forest turned the game on its head.
Detlef Esapa Osong netted twice and Ben Hammond added a third, but Liverpool debutant Bobby Clark pulled one back during the 10 minutes of first-half stoppage time.
The young Reds duly dominated the second period and were thwarted on several occasions by Forest goalkeeper Aaron Bott prior to Cannonier’s deserved late leveller.
Liverpool weathered an early storm in the form of a front-foot, high-tempo start from Forest, with Harvey Davies producing a superb reaction save to tip a powerful Osong drive onto the crossbar inside the opening minute.
Having gained a foothold, the visitors strung together a quality move that earned them an 11th-minute lead as McConnell met Terence Miles’ inviting cross with a diving header at the back post.
But Forest soon drew level through Osong, who showcased nifty footwork inside the box and accurately found the bottom corner.
Bridge-Wilkinson had to make his first substitution and direct a positional reshuffle shortly before the half-hour mark as debutant left-back Gyimah sustained a knock to the head and attacking midfielder James Balagizi came on.
And, just a few minutes later, Osong made it 2-1, the striker racing down the Forest left prior to beating Davies with a near-post finish.
Another Liverpool change was required when McConnell was clattered into by Pharrell Johnson and the hosts quickly extended their advantage as Hammond slid home the loose ball amid a scramble following a corner.
However, the young Reds reduced the deficit back to one goal courtesy of Clark, the new arrival from Newcastle United controlling Johnson’s attempted headed clearance on his chest and firing low beyond Bott.
There was real intent about Bridge-Wilkinson’s side straight after the restart and Melkamu Frauendorf - filling in at right-back following Gyimah’s injury - saw a low strike repelled by Bott, before the Forest goalkeeper was at full stretch to divert Harvey Blair’s long-range curler wide.
Cannonier came on just after the hour and twice went close to equalising within minutes of his introduction.
First, Cannonier was unable to adjust his body in time to find the target from Clark’s pacy cross, before Bott denied the forward after Balagizi had surged through midfield and found him with a pass.
A deliberate handball saw Forest’s Zach Abbott dismissed for a second booking with four minutes remaining and there was still time for Bott to frustrate Cannonier with another save before the goal finally arrived.
Miles delivered into the area and Cannonier stooped to direct Luca Stephenson’s knock-down into the net.
Liverpool U18s: Davies, Miles, Gyimah (Balagizi, 28), Omoruyi, Bajcetic, Stephenson, Roberts, Frauendorf, Blair (Cannonier, 63), McConnell (Pilling, 41), Clark.
Unused substitute: Mrozek.