Nico has the '15 manual. Here's a link to the BR Section for the caliper screws:
https://www.nicoclub.com/service-manual ... 5%2Fbr.pdf
The exploded views in the R&I portion of each manual section are where you'll find torque specs. The legend will have either a white wrench on black or a black wrench on white, the former means torque is in Nm (Kg/M, Lbs/Ft), the latter is Nm (Kg/Cm, Lb/In). There are 3 different caliper setups depending on your particular ride, so find the appropriate exploded diagram.
For some reason the FSM's for most models don't seem to give torque specs for the caliper frame screws (what Nissan calls the Caliper Torque Member). However, they all state "remove with a power tool" in the R&I instructions, so frankly we just lock them up tight with an impact wrench. They're fine-pitch screws which will handle a lot of torque, so I'd say anything above 100 lbs/ft is sufficient.