All permanents on the battlefield (Springheart Nantuko attached to Overlord of the Hauntwoods).
Overlord of the Hauntwoods does not have summoning sickness.
Steps
Declare Overlord of the Hauntwoods as an attacker.
Overlord of the Hauntwoods triggers, creating two tapped Everywhere land tokens.
When the Everywhere tokens enter the battlefield, Amulet of Vigor and Springheart Nantuko trigger twice.
Resolve both Amulet of Vigor triggers, untapping both Everywhere tokens.
Holding priority, activate the Everywhere tokens by tapping them, adding ({1} magic symbol) ({G} magic symbol) .
Resolve the first Springheart Nantuko trigger, choosing not to pay and create a 1/1 Insect creature token.
Resolve the second Springheart Nantuko trigger, causing you to pay ({1} magic symbol) ({G} magic symbol) to create a token copy of Overlord of the Hauntwoods.
When the Overlord of the Hauntwoods token enters the battlefield, it triggers, creating two tapped Everywhere land tokens.