Here are 2 great Triangle setups for no Gi, from the closed guard.
It can be tough to set up a Triangle choke in No Gi grappling because you don’t have the grips that you have in Gi BJJ for control. You have to use underhooks and overhooks and adjust how you hold onto someone’s wrist. Take a look at this first setup video.
Video Credit: ChewJitsu
Here’s a great video with a different setup from Firas Zahabi at Tristar Gym.