English

1)In English nephew is son of your(or your spouse's) brothers or sisters.
2)niece same as nephew, but is daughter of your(or spouse's) brothers or sisters.
3)Brother-in-law is your spouse's brother.
4)Sister-in-law is your spouse's sister.
5)Father-in-law is your spouse's father.
6)Mother-in-law is your spouse's mother.

It shouldn't be too hard, if Chinese will be a lot harder!

1) nephew
Middle English nevew, from Anglo-French nevou, neveu, from Latin nepot-, nepos grandson, nephew; akin to Old English nefa grandson, nephew, Sanskrit napāt grandson

2) niece
Middle English nece granddaughter, niece, from Anglo-French nece, niece, from Late Latin neptia, from Latin neptis; akin to Latin nepot-, nepos grandson, nephew — more at nephew
3) brother-in-law
1: the brother of one's spouse
2 a: the husband of one's sister b: the husband of one's spouse's sister
4) sisiter-in-law
1: the sister of one's spouse
2 a: the wife of one's brother b: the wife of one's spouse's brother
5) father-in-law
1: the father of one's spouse
2archaic : stepfather
6) mother-in-law
1: the mother of one's spouse
2archaic : stepmother

1) nephew (The sons of your siblings)

2) niece (The sons of your siblings)

3) brother-in-law (The brother of your partner OR your sister's husband)

4) sisiter-in-law (The sister of your partner OR your brother's wife)

5) father-in-law (The father of your partner)

6) mother-in-law (The mother of your partner)

1) nephew...姪兒;外甥 on boy
2) niece...姪女,外甥女 on girl
3) brother-in-law大伯,小叔,姊夫,妹夫,連襟;丈夫的姊夫,丈夫的妹夫
4) sister-in-law小姑;大姑;小姨子;大姨子,嫂嫂;弟媳,丈夫的嫂子;丈夫的弟媳
5) father-in-law岳父,老爺
6) mother-in-law 岳母,奶奶.

English not like Chinese, so the relationship is much simple. Just like father-in-law, both side father are father-in-law, if Chinese, than you have to call husband's father as 老爺, wife's father is岳父.

Hope this help!