Final answer:
Mikhail Chekhov, a former disciple of Stanislavski, created a nonrealistic BIOMECHANICAL style of acting and directing, emphasizing the actor's imagination and physical expression rather than Stanislavski's psychological realism.
Step-by-step explanation:
The former disciple of Stanislavski who created a nonrealistic BIOMECHANICAL style of acting and directing in sharp contrast to that at the Moscow Art Theatre was Mikhail Chekhov. Unlike Stanislavski, Mikhail Chekhov emphasized the power of the actor's imagination and physical expression in the craft of acting. Chekhov developed his distinctive approach after parting ways with Stanislavski, incorporating principles such as the use of Psychological Gesture to express the emotional and psychological state of the character non-intellectually. His methods became influential in their own right, diverging from Stanislavski's focus on psychological realism and the 'Magic If,' instead advocating for the actor's creative imagination and the physical embodiment of character.