What it does
"Super Nova" isn't an official Magic keyword or ability—it's not a mechanic that appears on real cards or in the comprehensive rules. There's an old card called Nova Pentacle, and "supernova" appears thematically in some sets, but no standardized "Super Nova" ability exists.
If you encountered this on a card, it's almost certainly a custom, fan-made, or proxy card rather than an official printing. Custom cards often borrow flashy names without standardized rules text, so the actual effect depends entirely on what's written in that specific card's text box—read it carefully and treat its wording as the rules.
For Commander specifically, remember that custom or unofficial cards aren't tournament-legal and should be cleared with your playgroup beforehand. If you can share the exact text printed on the card, I can help you parse how it actually functions.
