As dedicated hardware is becoming more prevalent in accelerating complex applications, methods are needed to enable easy integration of multiple hardware components into a single accelerator system. However, this vision of composable hardware is hindered by the lack of standards for interfaces that allow such components to communicate. To address this challenge, the Tydi standard was proposed to facilitate the representation of streaming data in digital circuits, notably providing interface specifications of composite and variable-length data structures. At the same time, constructing hardware in a Scala embedded language (Chisel) provides a suitable environment for deploying Tydi-centric components due to its abstraction level and customizability. This article introduces Tydi-Chisel, a library that integrates the Tydi standard within Chisel, along with a toolchain and methodology for designing data-streaming accelerators. This toolchain reduces the effort needed to design streaming hardware accelerators by raising the abstraction level for streams and module interfaces, hereby avoiding writing boilerplate code, and allows for easy integration of accelerator components from different designers. This is demonstrated through an example project incorporating various scenarios where the interface-related declaration is reduced by 6-14 times. Tydi-Chisel project repository is available at https://github.com/abs-tudelft/Tydi-Chisel.