Activate Thawing Glaciers by paying ({1} magic symbol) and tapping it, searching your library for a basic land card and putting it onto the battlefield tapped.
The land enters the battlefield, triggering Retreat to Coralhelm and Nissa.
Resolve the Nissa trigger, adding ({1} magic symbol) .
Resolve the Retreat to Coralhelm trigger, untapping Hope Tender.
Activate Hope Tender's second ability by paying ({1} magic symbol) , tapping and exerting it, untapping Thawing Glaciers and the basic land.
Activate the basic land by tapping it, adding ({1} magic symbol) .
Repeat.
Results
Near-infinite landfall triggers.
Near-infinite untap of lands you control.
Put all basic lands from your library onto the battlefield.