For the rice, heat a saucepan with a lid over medium to medium-high. Add the almonds and toast until light golden; transfer to a plate. Add the butter to the pan. When it foams, add the spaghetti and cook until browned, about 2 minutes. Add the rice, season with salt and pepper and stir to coat. Add two cups stock and bring to a boil. Reduce the heat to low, cover and simmer 15-18 minutes until the rice is tender; shaking the pan occasionally and adding stock if the rice is too dry. Stir in the almonds.
Meanwhile, season the chicken with salt and pepper. In a large skillet, heat the olive oil, two turns of the pan, over medium-high. Add the chicken and cook until brown, 3-4 minutes per side; transfer to a plate. Add butter to the skillet. When it foams, add the spring onion whites, thyme and garlic; season with salt and pepper. Swirl the skillet for a minute or two; whisk in the flour and then the wine. Simmer for a few seconds to reduce slightly, and then whisk in the stock. Bring to a bubble, return the chicken to the skillet and simmer until the chicken is cooked through, 3-5 minutes.
Transfer the chicken to plates, pile the rice alongside. Stir the spring onion greens and the lemon juice into the pan sauce. Spoon the sauce over the chicken and rice, and serve.