Can I run a node on a single board computer, like a Raspberry PI?

Raspberry PI is quite competent, is it enough for a nano node? I have a great network of 100/100 Mbit/s.

While the nano protocol is one of the most light-weighted in existence, it’s normally not recommended to do that. The CPU, Memory and Bandwidth would probably be fine but the main problem is disk IOPS. You need a good SSD for proper performance. The minimum recommended hardware is 2 core CPU, 2GB ram, SSD drive and a decent network of at least 10Mbit/s. I would recommend 4 cores (or virtual cores), 4-8GB RAM, SSD and 100 Mbit/s network. More RAM will ease the disk I/O.