What you need for this combo is:

x1 Sacred Phoenix of Nephthys
x1 Goka, the Pyre of Malice

The actual combo:

You'll need to summon Sacred Phoenix of Nephthys using any given way of choice. The fastest way is using Hand of Nephthys with one random monster. Special Summon Goka, the Pyre of Malice, using his first effect. Destroy the Phoenix with it. Next Standby Phase, you will get a Fireball Token if Goka is still on the field, AND clean the backrow for Special Summoning Sacred Phoenix of Nephthys.