Yes, you can paint the chair rail the same color as the wall for a cohesive and seamless look. This approach can create a sense of continuity in the room, making the space feel larger and more unified. By using the same color on both the wall and chair rail, you can emphasize other design elements in the room, such as artwork or furniture. Additionally, painting the chair rail the same color as the wall can help to simplify the overall color scheme and prevent the room from feeling too busy or disjointed. However, if you want to add visual interest or contrast, you can consider painting the chair rail a different color to create a bold statement or highlight architectural details. Ultimately, the decision to paint the chair rail the same color as the wall depends on your design preferences and the overall aesthetic you want to achieve in the space.