In this paper, an asynchronous and decoupled Hardware-In-the-Loop simulation of a DC nanogrid is presented. The DC nanogrid is a recent way to solve problems presented in traditional power generation, such as low efficiency, pollution, and cost increase. The complexity of this kind of system is high due to the interconnection of all the composing elements, making the use of HIL simulation attractive due to its advantages regarding computational power and low solution time. However, when a nanogrid is simulated in commercial and personalized platforms, all the elements presented are solved at the same integration time, even if some elements could be solved at smaller integration times, causing a slowdown of the system solution. The results of the asynchronous HIL simulation are compared with a synchronous HIL simulation with an integration time of 425 ns, and also with an offline simulation performed in PSIM software. The proposal achieves an integration time of 200 ns for the fastest element and 425 ns for the slowest, with an error of less than 0.2 A for current signals and less than 2 V for voltage signals. These results prove that the asynchronous and decoupled solution of an HIL simulation for nanogrid is possible, allowing each element to be solved as fast as possible without affecting the accuracy of the result, as well as simplifying programming.