Mix the oregano, rosemary, salt, and black pepper in a small bowl. Set aside.
Heat the olive oil over medium heat in a large deep lidded skillet or pot. Add the chicken sausage and cook until browned and crisp, about 3 minutes per side. Transfer to a plate, leaving the oil behind in the skillet.
To the same skillet, add the shallot and garlic and cook, stirring constantly, until fragrant, about 1 minute. Add the spice mixture and orzo, and stir to toast until golden brown and fragrant, 30 to 60 seconds.
Add the broth along with ¾ cup of water, stir, scraping any brown bits stuck to the bottom.
Increase the heat to high and bring to a boil. One boiling, cover, reduce the heat to low, and simmer until all the liquid is absorbed and the orzo is al dente, 9 to 12 minutes, stirring halfway through to prevent sticking (cooking time may vary by brand).
Add the peas, spinach, lemon juice and zest, and parmesan cheese and stir until the spinach is wilted, about 2 minutes. Remove the skillet from the heat, return the sausage to the skillet, and mix well to combine. Taste and season with additional salt if desired.
To serve, divide evenly among 4 bowls.
