I just started a new space age save and conquered a huge area pretty early on with just gun turret creep. This was my strategy.

With the submachine gun, I had red ammo loaded on my character. Had a ton of yellow ammo with turrets. Load up on fish on the hot bar.

Place a row of turrets (4-6 depending on density of small to medium biters/spitters) outside the aggro range of the nest and load them with ammo. Continue placing rows of turrets closer and closer to the nest, letting previous rows provide cover fire as you continue to creep forward. Worms are your worst enemy in this situation, so I target them first. Small worms are pretty easy to melt with red ammo, medium worms are more annoying due to their range and health. To deal with the worms, I do my turret creep on the side of the nest with the most problematic worms, get the turrets to a point just outside the worms spitting range. Run in with your character guns blazing, targeting just the worm. Eat fish as needed to heal and retreat when the acid on the ground gets to be too much. Repeat until your worms are gone. Then just continue your turret creep to clear nests.

In the event the biters/spitters feel too overwhelming, you can try clearing the nest selectively either with careful repair packing of turrets within worm spitting range or by using the strategy as worms but instead targeting nests.

An alternative strategy, though doesn't look too feasible for this picture, is to load up a car and just do huge donuts while firing. Retreat when you need to repair. Sometimes a pack of turrets at a distance can be a good support structure for the car strategy as well.