A few quick tips:
Use a drainage layer under the substrate, such as LECA (Lightweight Expanded Clay Aggregate) or large diameter gravel. Make it deep enough to keep the substrate above the level of any water that fills up in the bottom of the tank. The substrate can be sphagnum moss, ABG mix, or whatever your research suggests.
I’d highly recommend LED lighting, but don’t get too bright of a bulb. Since the nano tank is short and small, it’s easy to over-light it, which will be bad for most plants.
You may also want to add a small (40mm) PC fan (with controller to adjust speed). The fan will keep the air moving to reduce mold. It will also encourage healthier growth in plants. However, some species don’t like much air movement, so know your plants’ culture requirements before buying a fan.