You can at later rollup hooks (it doesn't make sense to access chunks that don't exist yet).
Actually, there are SSR frameworks being built on top of Vite such as SvelteKit [1] or vite-plugin-ssr [2] (vite-plugin-ssr is not a framework but gives you a similar DX than Nuxt/Next.js; I'm its author), and many people are implementing custom SSR solutions.
Join our Discord #ssr channel and ask us questions https://discord.gg/PkbxgzPhJv ;-).