Honestly, dark shades will prevent you from providing adequate light for even the lowest light plants and Fittonia is not one of those. Incandescent lights emit light in the wrong part of the light spectrum for plant growth. CFL's are beneficial for low light plants as long as they are left on for at least 8 hours each day and are no more than a couple of feet away from the plant.
Fittonias do require the increased humidity that a terrarium provides. Drainage material is usually recommended, but not essential as long as you are very careful not to water too heavily or too frequently. Keep the soil moderately damp, but not wet.