Explain the literal figurative significance of "milk" in this chapter?

Without knowing what specific chapter you are referring to, it is difficult to give a definitive answer to your question.

Mother’s milk is the primary source of sustenance for newborn babies. Because of this, mother’s milk symbolizes life, love, and a mother’s responsibility to her child. Sethe has a complicated relationship with mother’s milk. As a young girl, her own mother was constantly working in the plantation fields, and she had to share her caretaker’s milk with the white babies on the plantation. The white children would be nursed first, so sometimes Sethe would go without. So, when Sethe has her own children, she resolves to always have enough milk for her own babies. Tragically, her breast milk gets “stolen” by the schoolteacher's nephews. This incident traumatizes Sethe, not only because she was sexually assaulted, but also because she feels as if she failed her children. Interestingly, at the same time that Sethe hopes for Beloved’s forgiveness for killing her, she also hopes that Beloved will forgive her for the stolen milk. This demonstrates how powerful a symbol mother’s milk is for Sethe. Though is it a symbol of defilement and slavery’s horrors, it is also a symbol of her love and dedication to her children.