Nikos’s Archetype of Endurance prevents you from targeting any of his creatures (not that you have much to target them with), so the tricks need to come from your side of the table. Your Felhide Spiritbinder should help you find additional blockers, and in doing so, whittle down Nikos’s attacking forces at the same time.

1. Tap an island to add , a swamp to add , and two mountains to add (one used as generic mana) to your mana pool.
2. Spend and tap Felhide Spiritbinder to activate Black Oak of Odunos’s ability and give it +1/+1 until end of turn. Black Oak of Odunos is now a 1/6 creature.
3. Spend to cast Triton Tactics on Black Oak of Odunos and Felhide Spiritbinder, untapping both creatures and giving each of them +0/+3 until end of turn. Black Oak of Odunos is now a 1/9 creature. Felhide Spiritbinder is now a 3/7 creature.
4. Felhide Spiritbinder’s ability triggers. Spend to activate its Inspired ability, targeting your Doomwake Giant. You put a token that’s a copy of Doomwake Giant onto the battlefield.
5. Both Doomwake Giants’ abilities trigger, giving all of Nikos’s creatures a total of -2/-2 until end of turn. The Archetype of Courage and the Lagonna-Band Elder are both reduced to zero toughness and die. Archetype of Endurance becomes 4/3, and Colossus of Akros becomes 21/21.
6. Assign the nontoken Doomwake Giant (4/6) to block Archetype of Endurance (4/3).
7. Assign Black Oak of Odunos (1/9), Felhide Spiritbinder (3/7), and the Doomwake Giant token (4/6) to block Colossus of Akros (21/21).
8. Because Archetype of Endurance is blocked and Colossus of Akros is unable to deal any excess damage against a total of 22 toughness, you survive this combat phase at 1 life.