Heat oil in a large frying pan over medium-high heat.
Add chicken, and cook, stirring occasionally, for 3 minutes or until browned. Transfer to a plate.
To the same pan, add curry paste and coconut milk. Stir to combine. Cook, stirring, for 3 minutes or until aromatic.
Return chicken to pan.
Add sugar, tamarind paste, fish sauce and potatoes. Cook, stirring occasionally, for 3 minutes.
Add coconut milk and water. Stir to combine. Bring to a boil.
Simmer for about 30 minutes or until the chicken and potatoes are cooked through.
Stir in lime juice. Simmer for another 5 minutes.