As nouns the difference between nonperformance and nonexecution
is that nonperformance is a failure to perform a task, especially a task that one was legally bound to do while nonexecution is failure to execute or perform.
nonperformance
English
Noun
A failure to perform a task, especially a task that one was legally bound to do.
See also
* noncompliance
nonexecution
English
Noun
(-)
Failure to execute or perform.