These two buildings rarely come down to a coin flip, because they are not really competing for the same buyer. Nexus is a large Denny Triangle high-rise built around walk-to-work proximity to Amazon and South Lake Union and a full amenity deck. Koda is a smaller International District mid-rise built around a more historic, transit-rich neighborhood. If you already know which neighborhood you want to live in, that usually settles most of the question before we ever talk floor plans.
Where it gets interesting is the tradeoffs inside each choice. Nexus gives you the deeper amenity base, the 99 Walk Score, and the scale advantages of a 389-unit building, at the cost of more in-building resale competition and a published entry point from $650K. Koda gives you a lower-density, 204-unit building in a neighborhood with genuine character and one of the best transit positions in the city, typically at a more accessible price. Neither is better in the abstract. They are better for different people.
Before you commit, I put the specific units side by side on monthly cost per square foot, parking, view and floor, and the building's current HOA reserve and assessment position. With Koda I also pull recent closed comps in the International District, since the smaller building gives you fewer in-building data points to lean on. That comparison, not the marketing, is what tells you which building is the right buy for you.