Hilary.,
Please find the answer below:
Nexus:-
http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/5_x/nx-os/system_management/configuration/guide/sm_nx_os_cg/sm_9snmp.html
3850:
http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/network_management/command_reference/b_nm_3se_3850_cr/b_nm_3se_3850_cr_chapter_010.html#wp1824853750
2960:
http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960x/software/15-0_2_EX/network_management/command_reference/b_nm_15ex_2960-x_cr/b_nm_15ex_2960-x_cr_chapter_010.html#wp1824853750
HTH
Regards
Inayath
**Plesae rate if this is helpfull.