For any reason you forgot to include any loading in the analysis. Please post here your FEMAP model and we can take a look to it.
Your FEMAP model is fully PLOT PLANAR based in 2-D triangular elements, this means that your FE mesh is not exported at all to the NX NASTRAN solver, then the error. You need to create a valid 3-D solid mesh.
The first step is to check the validity of the 3-D solid geometry using command GEOMETRY > SOLID > CLEANUP, the result is the following:
Solid Cleanup 1 Solid(s) Selected... Beginning Cleanup of Solid 1... Removing Redundant Geometry... No Redundant Geometry Found. Cleaning Geometry... No Cleaning Performed on Geometry. Removing Small Features... 1 Spike(s) Found. 1 Small Edge Chain(s) Found. 1 Sliver Face(s) Found. Small Feature Removal Complete. Optimizing Geometry... Geometry Optimization Complete. Saving Updated Geometry... Checking Geometry... Inconsistency between Surfaces 58 and 97 near (461.3335, 3000.5, 120.4017). Inconsistency between Surfaces 58 and 98 near (460.5051, 3001., 120.3574). Inconsistency between Surfaces 58 and 99 near (462.4492, 3000., 120.4592). Failed Geometry Checking. Cleanup of Solid 1 is Complete.
The best way to inspect your geometry is slicing the solid by two planes and hide components: here you are, this is not a massive solid part, but a box with THIN walls that you need to mesh with 2-D plate & shell CQUAD4 elements after smart creation of midsurfaces. Also you have SOLID portions to mesh with 3-D solid elements, then you need to MIX 3-D Solid & 2-D Shell elements, in thos case I suggest to use GLUE EDGE-TO-SURFACE to easily define the finite element model.
Well, you need to practice basic meshing tecniques, ask for training to learn how to ndo it, also take a look to my video where I explain how to solve a similar problem:
I'm totally beholden with your comprehensive answer. I wish I would ask earlier.
Aprenderé esta técnica siguiendo tu video.
Un atento saludo,