Can I take backup of those tables which are created with NOLOGGING in Oracle? Can I take backup of those tables with data which were created with NOLOGIING option in Oracle. 

Is it true that backup can not be taken for these tables and I can not restore my data if I have some crash or corruption.
You can. From backup (rman) perspective there is no difference between LOGGING and NOLOGGING tables.

What you cannot do is restore through NOLOGGING operation. That means that if recover procedure will encounter such operation in archive log it is currently applying table will be marked as INVALID.