Yes, its possible. Most NPP data is referenced by device pointers anyway. If you want to use a paritcular single output from one function as a particular single input to the next, just use the output pointer of one NPP function as the input to the next.
You cannot do what you are suggesting in code, however. That is taking two device pointers (two different outputs from previous function(s)) and attempting to add what they point to in host code. That is not allowed. If you want to add scalar device quantities like that, you’ll have to use a library routine to do so (e.g. cublasaxpy)
In short, you cannot do this:
in host code, in CUDA. That is dereferencing a device pointer in host code. Illegal.
I don’t happen to know what that particular parameter expects for that function. But you need to make sure if it is a scalar quantity you are passing it correctly, and if it is a pointer you are passing it correctly.