Yes I'm responding to an old thread.
In Alberta: No provincial license required. Counties may vary, but so far there is no county requirement. Most cities require a business license, most villages do not.
No nursery license required.
Some pesticides require a provincial pesticide applicators license. Another bunch require a license if you are going to apply them on some one else's land.
A third bunch recommend training for risk reduction.
Check out the penalties for non-compliance in whatever jurisdiction you are in, and follow up by checking how well they enforce them. In the early years when every nickle counts, you may be better off ignoring the licensing, and pay your penalty when caught.