If you haven’t done so already, make your way to the Nexus and look for a Dock Manager along the northeastern corner of the Docking Bay area. Chat him up and he’ll tell you about some supplies that are apparently being smuggled out of the Nexus. This starts the quest "Task: Investigating Embezzlement".
To complete this quest you need merely find three shipments scattered about the Nexus. Let’s get to it, then! Head to the western end of the Docking Bay/Common Area and from the Arms and Armor Merchants head south, then turn east at the ramp leading up to the second level, near which you’ll find the first "Transferred Goods" crate. Scan it, then head to the Habitation Deck.
From the Tram Station head east through a door, then down some stairs. Turn south and go through another doorway to find a crate in the northwestern corner of the lab. Next make your way to the Cryo Bay, head east from the Tram Station, go down some stairs, then turn south to find the final "Transferred Goods" crate. Once all three are done, this quest is over, sans for a trivial Email "Stolen Nexus Goods" you’ll receive back on the Tempest.