A lot of butterflies. Completely changes Native-French relations. Algonquin tribes that Champlain allied with were at war with the Iroquois, and Champlain helped kill some of their chieftains (via. rifle). It made the Iroquois hate him but gained the respect of local Algonquin tribes. Unfortunately, those tribes were dwindling anyway. If Champlain ends up finding Iroquois before Algonquin (not unthinkable) there's a good chance he'd help the Iroquois wipe them out, or perhaps negotiate a peace treaty between the Algonquins and the Iroquois.
Long term however it's going to change a lot. If the Iroquois remain French allied, British settlers are going to be very hard pressed to settle territory up areas like the Hudson. Iroquois raids penetrated far in there IOTL, but the Iroquois were nominally paid off by the British and sent to fight up north. With the aid of the Iroquois, up until maybe a Seven Years War-type analogue British settlement is going to be harassed and many colonists are going to be frustrated.
That's how I'd ballpark it anyway. I think in the short-term the support for the French would be huge, but in the long-term the Iroquois aren't necessarily married to them- and if the Iroquois remain with the French, assuming they have similar colonial attitudes to OTL, things might bode even worse for them if French colonies in NA aren't viable or are occupied again.