The reason blocking your nose stops your taste is your nose and taste buds work together to allow you to taste.
Your nose nerves and your taste buds are connected together and work together to send the taste to your brain.
It's normal to lose taste when your nose is blocked, stuffy, have a sinus infection etc.
Smell is indeed connected to your taste.
Having a blocked nose can lead to you not being able to taste sense your taste buds and nerves in your nose work together to identify taste.
It's normal to lose your sense of taste with a sinus infection, cold or stuffy nose or the flu or even the new Covid-19 virus.
Yes a sinus infection can cause a loss of taste.
Whenever I have a sinus infection I lose my sense of taste until the sinus infection goes away.
The same is true when I have a stuffy nose i will also lose my loss of taste until the stuffy nose goes away.
Your smell and taste is connected because your taste buds and nose work together to identify taste.
The way it works is that your taste buds of your tongue identify taste, and the nerves in the nose identify the smell.
Both of your taste and smell senses are connected and both of those sensations are communicated to your brain, which then also integrates the information so that flavors can be recognized and appreciated.
Without being able to smell your taste can go away either partially or fully.