The Config guide tells us how to do this.
http://www.ciscostadium.org/en/US/docs/switches/datacenter/mds9000/sw/4_1/configuration/guides/cli_4_1/snmp.html#wp1352789
I also would like to know how to send only Config change traps to a snmp host. This trap will trigger a configuration backup to be pulled by the NCM.
I have not been able to get this support on NX-OS. IT is currently supported in IOS with the following syntax
snmp-server host 10.10.10.10 informs version 2c STLCARDSD0TC0M1 config
Does NX-OS have an equivelent. The key is the "config" on the end to send only config change events to this host.