Nil tds return mandatory or not

no Nil TDS return is not mandatory but you will have to file a declaration for the same on TRACES. there is no time limit I am aware of but the sooner the better. you can see the TRACES tutorial for how to file it.

IT IS NOT MANDATORY TO FILE NIL RETURN OF TDS 

It is not mandatory to file nil TDS return if you have not deduct TDS for any quarter.

However you have to file a declaration for non filing of TDS Return. 

The Deptt. has introduced a new functionality in the TRACES site wherein the persons who are not required to submit a return of TDS due to non applicability in any particular quarter shall have to submit a Declaration for the same on TRACES. Procedure for filing of Nil TDS return/ declaration for non filing of TDS statement is given below: 

1. Login through your registered id at www.tdscpc.gov.in (TRACES site) 

2. Go to Statement/Payments TAB after login > Declaration for Non filing of TDS statement