The head of the serpent is interesting as you note. The pattern breaks at the neck and there is the second short line of holes to the east that does not have a matching set on the west side of the line unless it is completely buried. A lidar or GPR survey may help understand that slope.
I found this serpent amulet on Etsy [0] that implies that the word Amaru means serpent in Quechua so I looked that up and found a nice description that may help explain breaking the pattern at the head. [1]
[1] https://en.wikipedia.org/wiki/Amaru_(mythology)
The Amaru serpent could manifest with several different heads so the people who made this example may have used the natural bowl to show their local version of the Amaru that they believed would provide their desired results - rain, crops, etc.
[0] https://www.etsy.com/listing/1487839343/peruvian-hand-carved...
Another thing that I have not seen considered is that these holes may have been used to hold vessels for storing wine or brandy made from grapes that grew in the region. Evidently Pisco is a type of wine produced in the Nazca region in pre-Columbian times. [2] The vessels in the photo which store the wine may be a design passed down since ancient times. If you have a series of holes in the ground of a consistent size and you produce lots of vessels for storing something that you produce locally and those vessels are size to fit the holes in the Band of Holes then maybe this was their wine storage site.
[2] https://www.exploorperu.com/blog/peru/pisco-culture/
As another possible explanation, though it does seem possible it also seems a bit far-fetched and would definitely require some drone study I found this site [3] which claims to see pictograph symbols in the chain of holes when viewing the site from Google Earth satellite view taken on a specific date.
[3] https://www.ancient-origins.net/opinion/mysterious-holes-per...
It's interesting whatever they were doing.