Not sure, if a DSLR is the right choice for you. The Nikon 5500 has no pivotal display, I think the first Nikon that has is a D750 which is way beyond your price range of 1000$.
I am not into videography, but I heard that the count of autofocus-pixels might reduce the video fun a bit.
About the Panasonic, isn't it MFT? MFT has some pro's and con's compared top APS-C.
Camera wise, the Nikon is a nice thing tho. The 50mm fixed (fx) and 35 mm fixed (dx-format) are quite affordable and have a superb picture quality. But I think you might prefer a zoom with some range for filming. I am using a D3300, it offers the same picture quality. The worse autofocus doesn't affect me, as I am rather into nature fotography, anyways.
Some Nikon D3300 examples (+ Pentax K50 and Pentax 35mm DSLR Pictures):
https://www.elcarnicero.de/koken/index.php