NX/Simcenter never actually "imports" results (i.e. into the .fem/.sim file database). The Post processor merely attaches to the solver results file. Consequently, there is no "export" results capability.
You appear to be looking for a results file translator, which Simcenter does not provide.
It's probably easier to look for a multi-CAE viewer than expect to convert op2 to rst or odb for instance...
Paraview is one of them, there was an op2 reader available last time I checked... One that I would recommend for this type of work is Ceetron Analyzer Not a Siemens product, but does wonders with NX Nastran op2 and many of the other formats you mentionned.