Hey all! Thanks for your replies!
OK, I was using: GitHub - kow/glinetpineapple: Wifi Pineapple firmware for for GL.iNet GL-AR150, the 1.0.6 version.
Some notes:
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When changing firmware, “do not keep current configuration”
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When uploading is done, WAN port should be used, and Pineapple DHCP will give you an IP address correctly 
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Connect to its web interface, when it asks to press the reset button, press the one in AR150, and set a password. Done! Now it’s working…
All the hardware is pretty similar, however the NANO has 2 wlan’s but this on only one, so a few things (internal scripts for example) need some tuning… also, you will be connected to the AR150 via WAN port and that will be like the USB eth on the original NANO…
I’m playing with this and maybe come up with some script that will change the necessary things to make it work… also, I’m connecting my Alfa RTL8187 to the AR150 usb port so I can “emulate” the second interface… it could be cool to put 2 ar150 connected via the lan port both with Pineapple firm and use them as one nice wifi hacking device, right?
I will post here my research and notes… if any of you is playing with this same arrangement, ping me, and we can stay in touch… I will need some help maybe 
cheers!