Conor - 4 ranked wins
#1 fighters defeated (2):
Alvarez
Aldo
Top 5 fighters defeated (2):
Mendes
Poirier
Top 10 fighters defeated (0):
Khabib - 4 ranked wins
#1 fighters defeated (0):
Top 5 fighters defeated (2):
Barboza
dos Anjos
Top 10 fighters defeated (2):
Johnson
Healy
And to put it into perspective, here's Fedor's list:
Fedor - 12 ranked HW wins
#1 fighters defeated (1):
Nogueira 1
Top 5 fighters defeated (5):
Nogueira 3
Cro Cop
Arlovski
Sylvia
Herring
Top 10 fighters defeated (6):
Coleman 1
Hunt
Randleman
Schilt
Rogers
Fujita
Both Conor/Nate fights took place at WW and neither of them were ranked at WW.
Nate doesn't get the distinction of beating a #1 fighter either. He beat the #1 FW at WW.