Nikko is the first digital artist that got me hooked into Procreate.app. He is also the artist who, through his online courses, convinced me that I could crack the nut that is digital art. Whereas Mike Henry’s videos are free, Nikko charges a nominal fee for his tutorials. I think the tutorials are worth every penny, though.
What I appreciate about Nikko’s tutorials is his focus on how to think about composition and working from big to small. It is obvious his instruction is grounded in the fine arts, and much of what you will take away is applicable to any medium, not just Procreate.app or even digital.