Nihilism does not uphold race as a value any more than it tells us one culture is arbitrarily better than another. We’re all biological entities built with genetic code and then defined and refined through our intellectual capacities and our remarkable ability to adapt, overcome, and prosper.
Much of this success is due to the fact that humans are mentally malleable beings whose rise to the top of the food-chain has been a direct result of adopting new ideas and developing new tools and technology.
Race is a subset of species, sometimes referred to as a sub-species, and a species is defined as a group that can reproduce together. Organisms within a species group, like races, can reproduce together. Human races are relatively new creations, formed under the intense pressures of natural selection in the harsh environment of the last ice-age. Because races can intermix they will, it can’t be wrong in an evolutionary sense because it’s biologically and physically possible. The only limitation is geography and the speed of travel, that’s why human races have been preserved in many parts of the world. However, as everyone can tell these limitations of space and distance no longer hold true. Intermixing is what normally happens when separate populations come into contact; the only remarkable difference today is the scale of the event. Whereas in the past it was only a few individuals, for instance the European conquistadors that explored Central and South America centuries ago, now it’s entire populations. 
Because many of the physically characteristic traits of specific races are recessive genes, blue eyes and blonde hair for example, they will no longer show up in the superficial attributes of the hybrid population except in rare cases. This doesn’t necessarily mean that recessive genes no longer exist at all and go extinct; in fact since the goal of a gene is to spread as widely as possible they can actually gain from this. This demonstrates the very complex process of conflict and interaction occurring on the genetic level, far beyond what we are aware of at our own macroscopic scale.
We naturally grow and develop through continual interaction and synthesis
As even a cursory study of biology in the natural environment indicates there are a wide variety of strategies for personal and collective success, with success defined as adaptation to make the most of the surrounding environment. The individual freedom to choose your strategy, ideally with serious thought and consideration involved in the decision, is critically important because otherwise the trouble arrives when one despot, or authority group, tries to impose their own values and strategy upon others. This inevitably leads to dictatorship, authoritarian brutality, and eventual social collapse.
Actual events and technological developments have already far outpaced the traditional conceptions of race and reproduction. The real story is far more fascinating anyway when we consider the revolution in biotechnology. At some point in the relatively near future the tools and knowledge of biotechnology will progress to the point where genes, DNA, and the basic elements that build life are as fungible as Lego building blocks. This elemental simplicity is nihilism because it is ineluctable. Eventually we’ll be able to build life and rearrange it as desired. The potential is practically unlimited, for we can become literally whatever we want to be and anything becomes possible – we can cut and paste, edit out diseases, edit in new attributes, and even create entirely new life forms. The real issue is what do we create with these building blocks and what are the consequences?
To ask ‘is this technology good or bad’ is to ask a specious question because the technology is inevitable. We mustn’t hide from it or try and ban what’s physically possible because, like all technology, as fast as one narrow-minded clique rejects it another less conservative group picks it up and gains a massive advantage over the rest. Instead, it’s time to collectively develop the maturity and intellectual development to properly deal with the forcers and consequences of our tools.
“It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change.” – Charles Darwin