The outer wall of this crater is worn, with a number of tiny craterlets lying along the rim. The most notable of these is a tiny crater located across the northern rim. The satellite crater 'Nicholai B' is attached to the exterior of the southwest rim. The inner walls slope down relatively smoothly to the flat interior floor filled with lava. The only marking on the inner surface is a tiny craterlet in the northern part of the crater. Nicolai is from the Nectarian period, which lasted from 3.92 billion to 3.85 billion years ago.
| Nicolai | Latitude | Longitude | Diameter |
|---|---|---|---|
| A | 42.4° S | 23.6° E | 13 km |
| B | 43.2° S | 25.3° E | 13 km |
| C | 44.0° S | 29.0° E | 25 km |
| D | 41.7° S | 25.5° E | 6 km |
| E | 40.6° S | 25.3° E | 13 km |
| G | 42.8° S | 22.4° E | 11 km |
| H | 43.5° S | 26.8° E | 17 km |
| J | 40.5° S | 22.0° E | 8 km |
| K | 42.9° S | 28.2° E | 25 km |
| L | 44.1° S | 25.6° E | 13 km |
| M | 42.4° S | 29.0° E | 11 km |
| P | 43.1° S | 29.7° E | 30 km |
| Q | 42.3° S | 30.1° E | 26 km |
| R | 41.5° S | 25.9° E | 6 km |
| Z | 40.9° S | 21.5° E | 24 km |