To put it simply, biology is a natural science, whereas chemistry is a physical science.
Biology is the study of life, it encompasses all living things. There are certainly aspects of biology that are entirely chemistry-based, as it’s essential in understanding why and how life functions at a molecular level. I have heard biology described as “applied chemistry” before, which is accurate to a certain extent, but I cannot agree with fully. Biology goes beyond chemistry, there are many branches and sub-disciplines that delve into the intricacies of how different species interact in an ecosystem, or the processes of evolution (to name a couple).
Chemistry is a study dedicated to discovering new substances of which matter is composed, exploring the properties of different substances, and investigating how different substances react to each other to create new ones. It is just as nuanced and complex as biology (some may argue differently, that one is more complicated than the other). It is commonly thought of as a “central” science, as there are elements of chemistry in biology, physics, and geology.