This is one of two missions that can be completed upon arriving on Canal City, along with the mandatory "Search Canal City for thief".
Though this mission is entirely optional, it is a good opportunity to earn bolts. The Synthenoids becomes available at the Megacorp vendor upon arriving to this world, which creates a group of robots guardians that will shoot at nearby enemies when deployed. Though useful, it is not necessary against the enemies here, and is not affordable unless you have completed every single side challenge (space combat missions, hoverbike racing, and Galactic Gladiators arena battles) up until now.
Instead of crossing the bridge, after descending from your ship by the elevator, the promenade is found by taking the left path. There are several Megacorp Chickenbots found on the way here, which can easily be dispatched. Head through the tunnel here (with a blue holographic sign above it) to find a room with more Chickenbots, and a single Thugs-4-Less Henchman. These are relatively tough enemies which will fire an electric blast towards you; they are best defeated with the Seeker Gun or Blitz Gun, possibly with the Miniturret Glove for support or Gravity Bomb when encountered in large groups. Exit the tunnels to be confronted by four Henchmen. Go around the large floating globe in the center (destroying it nets you a skill point), kill the Megacorp Chickenbots and the Megacorp Chickenbot Generator producing them, then take the elevator shaft up.
After taking the elevator up, three Henchmen pose in place of mannequins, and will ambush you if you come too close. Take them out with the Blitz Gun, and a Thugs-4-Less attack ship will appear. This ship shoots fireballs at you, and is very durable; simply dodge the fireballs and use the Seeker Gun or Pulse Rifle to take it out. Cross the bridge, and defeat the Henchmen that jump out of the shop window, then proceed left to a fork: the path straight ahead leads to an elevator shaft upwards, while the left leads to another store and an apparent dead end (hiding a platinum bolt). Head across left first to take out the Thugs for bolts, then head up the elevator shaft. Defeat more Thugs, and another attack ship, and head across the bridge to a final store. Take out the last Henchmen and Chickenbots, then take the elevator shaft up. Claim the nanotech boost, and use the teleporter to return to your ship.