These commands are not mean to use for MDS NX-OS
On MDS switch you can use the command which to list snmp-server command structure and follow that structure
example:
conf t
term len 0
which | inc snmp-server
[3421467]. snmp-server user enforcePriv[o]
[3421468]. snmp-server user [o]
[3421469]. snmp-server user [o] auth md5
[3421470]. snmp-server user [o] auth md5 engineID
[3421471]. snmp-server user [o] auth md5 localizedkey
[3421472]. snmp-server user [o] auth md5 localizedkey engineID
[3421473]. snmp-server user [o] auth md5 priv
[3421474]. snmp-server user [o] auth md5 priv aes-128
Thanks