NVIDIA NeMo Agent Toolkit LangChain/LangGraph Integration

The `nvidia-nat-langchain` package is a subpackage designed for integrating LangChain and LangGraph with the NVIDIA NeMo Agent Toolkit (NAT). NAT is a flexible, lightweight, and framework-agnostic library that enhances AI agents with enterprise-grade capabilities like observability, profiling, evaluation, and orchestration. It allows users to leverage existing LangChain/LangGraph agents while benefiting from NAT's advanced features without significant code changes. The library is actively maintained, with version 1.6.0 being the current release, and follows a rapid development and release cadence.