If NCS do not find the configured hardware it will fallback to the CPU. This is most likely what happens in your case. NCS do not find the Nvidia encoding. I assume that the GTX 1060 also support encoding.
Test to run everything with Intel GPU and see if the encoding works. Typical is to update drivers for the Nvidia card.
When using hardware acceleration NCS will use some extra CPU load for administration of data streams and memory handling.
I have a dual Xeon server with Nvidia card. When I start recording NCS use both Nvidias´s decoding and encoding as below.
