I love how everyone just points out that it's impossible (or rather impractical) and nobody really cares to explain why.
The main factor here is that the Switch runs the Horizon kernel (which is loosely based on FreeBSD) and all the code and games "talk" to it through proprietary Nintendo code. (The majority of the code is written in C and derivatives)
Android applications on the other hand run on Linux through a Java Virtual Machine. (The majority of the code is written in Java).
Now, porting a Java Virtual Machine on Horizon is theoretically possible, even if it's difficult and tedious. But that would not be enough since ART (they still use ART, right?) is not a standard one and heavy modifications (which will be on an entirely different level of difficulty) would have to be done in order to run it under Horizon.
Now, sorry for any inaccuracies in my explanation but I wanted it to be as simple as possible.
If you really want this to happen it would be easier to port Android on its own on the Switch the same way Lakka was ported. It will not be easy, but it's feasible. Keep in mind that there is not really a point in this, since a powerful android phone or tablet can be yours for very little money nowadays.
The main factor here is that the Switch runs the Horizon kernel (which is loosely based on FreeBSD) and all the code and games "talk" to it through proprietary Nintendo code. (The majority of the code is written in C and derivatives)
Android applications on the other hand run on Linux through a Java Virtual Machine. (The majority of the code is written in Java).
Now, porting a Java Virtual Machine on Horizon is theoretically possible, even if it's difficult and tedious. But that would not be enough since ART (they still use ART, right?) is not a standard one and heavy modifications (which will be on an entirely different level of difficulty) would have to be done in order to run it under Horizon.
Now, sorry for any inaccuracies in my explanation but I wanted it to be as simple as possible.
If you really want this to happen it would be easier to port Android on its own on the Switch the same way Lakka was ported. It will not be easy, but it's feasible. Keep in mind that there is not really a point in this, since a powerful android phone or tablet can be yours for very little money nowadays.