Some have invoked Mo Katir, but Shelby is the correct answer and the similarities are undeniable. Once you see it, you can not unsee it. To whit:
Misplaced Early-Career Focus: Both started with an event far from their ultimate home. Shelby was an 800m runner, Narve was messing around with Half Marathons/10Ks early on.
Age: Shelby was age 25 in her breakthrough season, Narve is 24 but turning 25 in a month. These are late ages for such a breakthrough in the 1500.
Early Pro Career/Background: Both were mildly successful 5,000m runners at age 22-23 with a coach they'd had for years. Shelby ran ~15:00 in 2016 and 2017 and made two global finals but was not competitive in her races on the DL/World level. Narve ran 13:16, missing out on global finals, and was not competitive in his races on the DL/World level. They had improved to this level, but seemingly stagnated.
Coaches: Both Gjert and Jerry Schumacher are ferociously loyal to their system (my way or the highway), and believers in very high volume relative to their athlete's event. They're of course both Western coaches with a track record of success, and to the point of these breakthroughs not involved in any athlete ever busted. However, both had an athlete show up as "Likely Doping" in the Fancy Bears hack (Jager and Henrik).
"Found New Event in the 1500": Both broke through in the 1500 after semi-mediocrity in the 5000, flashing huge kicks that stood out vs. the competition while setting massive PBs. Narve 3:36 to 3:29 and a medal. Shelby 4:03 to 3:57 with a huge kick in multiple DLs. Both went from also-rans on the DL to contenders for the win.
The Myth of the New Event Thesis: Sure both had newfound success at 1500 in their breakthrough year, but it wasn't merely finding their event. Nordas just advanced in the gauntlet 5,000 prelim on less than one day's rest as numerous fresher sub-13 runners got bounced. Shelby set an American record and ran 14:33 for the 5K in 2018. Both athletes made gigantic strides and would have been factors in their old event of the 5,000 had they stuck with it as primary event. We can reject the new event notion.
Explanations Behind Their Success: Both credited the accumulation of hard work most of all. Otherwise, they'd talk about marginal improvements in diet, more altitude, slightly more mileage and making their coach's system work better for themselves. Narve has talked about not feeling pressured to run with Jakob, more Gjert focus. There was no talk of anything radically different being done from one season to the next or overcoming major injuries etc. This is unlike a Mo Katir (younger, got a new coach, finally had support, affected by pandemic etc.) or Ciara Mageean (injuries, new coach etc.) for a couple of examples.
Conclusion: There is probably more I am missing, and I want to be clear I don't 100% know/think Nordas is doping or anything like that. But I think if you examine every aspect of it, there is no more comparable situation out there. Pretty much every aspect of their rise and breakthroughs is identical. I like Nordas' personality and would like to believe his breakthrough is 100% clean. I felt the same with Shelby, but was always dubious of it at the time.