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While that's not the most terrible idea, the likelihood in a Niv-Mizzet deck is that the other spell you're casting is a burn spell that could do the same, and I have to feel that you're going to be better off casting it by itself, rather than putting all your eggs in one basket

Otherwise, all of these Taught by cards also cantrip when you cast them

And it's even better thanks to harmonize since you can do things like grab a ramp piece to make the mana you need for your finisher and then use that mana to harmonize Nature's Rhythm and find the finisher

Special Summon 1 FIRE Dragon monster from your Deck to the field