Use a protoplanetary disk
It's much denser than a nebula in deep space. It gets denser and hotter the closer in you get, and gas drag is important for planet building. According to this study, a disk around a young sun can have 1 Pa of pressure at 300K (closer in heat becomes a big problem). This is enough to make significant drag and heating at orbital speeds. Around a Jupiter like planet, the study gives a pressure of 1/3 bar at 300K, enough to not need a space suit.
This is about 45 times less dense than air since the gas is mostly hydrogen. But it is still enough to be looking at fighter-jet velocities instead of space-shuttle velocities. The disk will be in orbit around the star/planet, so velocities will be low relative to a circular equatorial orbit.
Say your ship is pressurized to pure oxygen at 1/5 bar, which is the same amount of oxygen at sea level. Not including nitrogen saves precious mass for the pressure hull.
The 1/3 bar of outside gas is at a higher pressure than the ships default atmosphere, which adds to the excitement for ill-prepared crews. The pressure could crush the delicate walls (it's easy to crumple a soda can). Or the hydrogen could enter through the tiniest leaks and mix with the oxygen.
The caveat is that this 1993 study is a rough estimate of the pressure-temperature curve, but it is at least plausible. I can't find newer numbers.