I don't think that SCL is one of the departure airports that qualify for baggage to be checked all the way through if you transfer int'l -> domestic at YYZ (unlike when you depart the US and select European airports), so I'd very much expect that you'd need to collect your baggage at YYZ and then drop it off again after customs.
90min is perfectly doable if everything goes smoothly, the major variable is how long it will take for your baggage to be delivered.
Is there a later YYZ-YYC segment you could book?