This is a filler episode from the Kurosuki Family Removal Mission arc.
After struggling with toad oil, Naruto learns to channel natural energy through intense focus. He uses Shadow Clones to accelerate his learning, a feat even Jiraiya couldn't achieve. Naruto Episode 156
Meanwhile, the Raikage prepares for a Five Kage Summit to address the Akatsuki and retrieve his brother, Killer B, from Sasuke. Naruto (Original) — "Raiga's Counterattack" This is a filler episode from the Kurosuki
Raiga Kurosuki wakes up and, finding Ranmaru unconscious, directs his rage toward Karashi. Meanwhile, the Raikage prepares for a Five Kage
Tenten is defeated by Raiga but later saves Ranmaru. Naruto, Neji, and Rock Lee struggle against Raiga’s lightning-boosted powers until help arrives.
Fukasaku marvels as Naruto achieves a "perfect" Sage Mode without frog-like physical mutations, surpassing both Jiraiya and the Fourth Hokage in this specific discipline.
Depending on which series you are watching, "Episode 156" refers to different events. Here are the summaries for the original series, Shippūden , and Boruto :