Macro to make a spell work to [@mouseover] or who I'm targetting

Hey Rdruid looking for a macro for my Nature’s Swiftness. I got:

#showtooltip Nature’s Swiftness
/cast Nature’s Swiftness
/cast [@mouseover] Regrowth

so far, but when I’m targeting someone without mouse hovering it won’t cast the regrowth (yet still cast nature’s swiftness). And without the '[@mouseover] for the Regrowth it won’t cast while hovering raid frame. Need the macro to allow casting onto mouse hover/target (pref raid frame by default, I assume).

Thanks, 3o.

#showtooltip
/cast Nature's Swiftness
/cast [@mouseover,help,nodead] [] Regrowth