High-Resolution X-ray Diffraction (HRXRD) is a well-established technique for the characterization and metrology of epitaxial materials encountered in a variety of important technologies such as nano, opto and power electronics. Traditionally the technique was mainly used for blanket films, and this is still a significant application. However, complex epitaxial nanostructures continue to grow in importance to enable advanced CMOS logic transistors that must combine high-performance with low power consumption and cost with scaled dimensions. Hence, the need to measure and analyze such structures becomes necessary. Several new transistor architectures being considered for logic nodes beyond 10 nm, including more sophisticated FinFETs, gate-all-around (GAA) FETs and the use of fully-depleted silicon-on-insulator (FDSOI) substrates. Equally varied is the range of epitaxial materials proposed, which include SiGe, SiP, Ge as well as III-V materials. Each of these innovations has specific challenges for both process development and control. In this presentation we will discuss the recent advances in HRXRD tools, measurements and analysis methods for the characterization and metrology of arrays of nanostructures on patterned wafers with a spot-size < 50 µm and production worthy throughputs and reliability. We will discuss how HRXRD measurements such as high-speed reciprocal space maps (RSMs) are used to determine the composition, strain, and quality of epitaxial nanostructures, and illustrate the challenges and results using representative examples drawn from our recent collaborations.