### Clue: What Puck uses in an instant assuming Nick's close to the margins of reality (8)
### Answer: TRICKERY 
 ### Explanation: Definition: What Puck uses
 [ TRICE(an instant in time) **containing**(assuming) **the last letter of**(…'s close) "Nick" ] **plus**(to) **the 1st and last letters of**(the margins of) "reality".