Yep, it can be done. Though most of our experience has been on the Minion, I know we've done some work on the Flongle too.

Amplicon from real time PCR it's to short which not suitable for Nanopore sequencing

Well you are right to a degree. As Worawat says, the first few dozen bases are noisy/low base quality but nonetheless you can sequence amplicons. I wouldn't recommend anything short like 20-50 bases. We're doing work with our own in-house oligos which range around 3000-5000 long amplicons, we'll see data on shorter amplicons soon which I suspect will also work. We chose longer amplicons to reduce the primer plex not because the first few hundred bases read quality is low (which it isn't). There's also size factor too, some claim longer amplicons produce more data but this is all relatively new and there's no definitive guide on the best combination of doing things to get the best data out on this platform. Part of the excitement of this platform.

@Can and @Worawat - Thank you for your responses. We have used MionION to successfully sequence conventional PCR products that are as small as 120 bases. However, I was wondering if anyone had experience sequencing real-time PCR products and if these required additional product clean-up prior to sequencing.