Do you have the dokkan'd TEQ Cell? He and SSB Goku TEQ together can do 6 million+ damage to SS3 Goku. Set SSB Goku as the leader to get the +30% damage per TEQ orb obtained, then get as many TEQ orbs on the board as you can, then use Cell to fire off the super. Cells passive is +10% attack per ki orb obtained, which stacks with SSB Goku's leader skill to become ridiculous.
The key to nuking is don't just fire off a normal super, you need to get as many TEQ orbs as possible. Right now I'm doing the event using 2 senzu beans (just in case), then a PHY puar (str orbs turn PHY), INT Puar (PHY orbs turn INT), and TEQ Oolong (INT orbs turn to TEQ). I use the color changing items in that order, and combined with SSB Goku's passive, usually roughly 75% of the board is TEQ orbs. Maybe overkill, but those nuke numbers are so satisfying.