Are you referring to MAC-IP binding in a DHCP response? This would be available from a Meraki MX appliance or Meraki MS switch that's capable of providing DHCP services, bindings, reserved ranges, etc. On the Meraki APs, when running an SSID in NAT mode, the AP will be the NAT boundary and DHCP server but it's not configurable with preset MAC-IP bindings for the clients. It could be used for simple guest networking for example where you wouldn't know the MACs in advance anyway. Other option if you only have APs is to run the SSID in bridge mode and use any 3rd party DHCP on whatever VLAN you bridge the SSID to.
