Yes, but given the cost of quickened spell, I find it's best used in situations where you need your action for things like dashing, dodging, escaping a grapple, etc. But if you know you have a rest coming up, or that the deadly monster is about to go down, go for it.
As a sorcerer, can I use Quickened spell to cast a cantrip (like firebolt) as a bonus action then use another cantrip as an action?
Yes, but given the cost of quickened spell, I find it's best used in situations where you need your action for things like dashing, dodging, escaping a grapple, etc. But if you know you have a rest coming up, or that the deadly monster is about to go down, go for it.
In fact, you can cast as many cantrips with a casting time of an action as your action economy allows.
"Not all those who wander are lost"
Very powerful with 2 levels of warlock for agonizing blast.