pfsense NAT gateway to Mikrotik Routerboard

I have a Netgate pfsense box and I want that all my traffic goes by the pfsense firewall.
The pfsense should only work as a firewall with additional packages like snort and ntopng and should be in the network 192.168.10.0/24 on ether1 on the Mikrotik with address 192.168.10.254
And the other interface of the pfsense is connected with our ISP and has a static IP.
On the Mikrotik I want 2 other subnets 192.168.20.0/24 and 192.168.30.0/24 but the default gateway off the two subnets should be the pfsense firewall.
So all the traffic from the three subnets should be routed to the pfsense firewall only for the outside traffic.
The Mikrotik may not function as NAT router.
See attachment.
Can anyone help me realise this please?
Untitled Diagram.png