So your statement from post #3 was not true.
If you look on properties of both libraries NAND and INVERTER (by RMB→properties in Lib Manager), you can find a difference in attached technology library. INVERTER is attached to your technology library (in this case tsmc18) while NAND to dummy library called cdsTechDefLib. So, in palette of layout view in one cell you can see a lot of physical layers, while in other only background and text.
During creation of NAND library you have not attached library to your technology.
To fix it do following:
1. close open cells and close data (CIW→File→close data - select all and close)
2. go to (recall from my short memory) CIW→Tools→Technology manager, in tech manager window, choose attach button and point to you design library (NAND) and attach it to tsmc18.
3. Refresh memory: CIW→File→refresh
4. Create new layout view of your cell.