Place the chicken thighs in a medium bowl, season with salt and pepper and set aside.
In a large deep pan, heat the olive oil over medium-high heat until shimmering.
Add the shallot and red pepper flakes and cook for 1 minute, until the shallot starts to soften. Add the chicken, potatoes, squash and curry sauce to the skillet. Bring to a simmer, turn heat to low and cover. Cook, stirring and scraping the bottom of the pan occasionally, for 12 minutes.
Uncover, and add the zucchini, fish sauce and lime juice. Season with salt and pepper, to taste. Raise heat to medium-low and simmer, stirring frequently, until chicken is cooked through and vegetables are tender, about 7 to 10 minutes.
Serve over rice and garnish with green onions, cashews, lime wedges and cilantro.