Yes, but again, if we are doing this only to shed it into space (on a terraformed mars), then we are importing it to Mars to reduce the total load bearing capacity of the solar system in the future.

Furthermore, you have to spend the colossal amounts of energy to move atmospheres worth of nitrogen around the solar system.

There is a small irony that nitrogen is currently used as gas thrusters for rockets. We're dumping earth's nitrogen into space already, granted in very very small amounts. But harvesting the earth's atmosphere for nitrogen would be very bad in the longer term if done in bulk.