The query could be improved by adding her birthdate, birthplace, and any information on parents or siblings that you know.

I did find her on the 1900 census, which says she is born in Norway June of 1870. If you click on the link, you can also click around on the other family members to get their information.

https://familysearch.org/pal:/MM9.1.1/M99B-Q95

Name: Nettie Engebritson
Titles & Terms:
Residence: Medo Township, Blue Earth, Minnesota
Birth Date: Jun 1870
Birthplace: Norway
Relationship to Head of Household: Wife
Spouse: Albert Engebritson
Spouse's Titles & Terms:
Spouse's Birthplace: Iowa
Father:
Father's Titles & Terms:
Father's Birthplace: Norway
Mother:
Mother's Titles & Terms:
Mother's Birthplace: Norway
Race or Color (expanded): White
Head-of-household Name: Albert Engebritson
Gender: Female
Marital Status: Married
Years Married: 9
Estimated Marriage Year: 1891
Mother How Many Children: 4
Number Living Children: 4
Immigration Year: 1886
Enumeration District: 0026
Page: 1
Sheet Letter: A
Family Number: 1
Reference Number: 2
Film Number: 1240758
Image Number: 00191
Household Gender Age
Spouse Albert Engebritson M
Nettie Engebritson F
Child Clark Engebritson M
Child Lewis Engebritson M
Child Andrew Engebritson M
Child Esther Engebritson F

1910 census:

https://familysearch.org/pal:/MM9.1.1/M2LF-NCM

Name: A C Engebretson
Birthplace: Iowa
Relationship to Head of Household: Self
Residence: Medo, Blue Earth, Minnesota
Marital Status: Married
Race : White
Gender: Male
Immigration Year:
Father's Birthplace: Norway
Mother's Birthplace: Norway
Family Number: 72
Page Number: 4
Household Gender Age
A C Engebretson M 48y
Spouse Nettie Engebretson F 39y
Child Clark Engebretson M 17y
Child Lewis Engebretson M 11y
Child Ester Engebretson F 10y
Child Andrew Engebretson M 14y
Child Ruth Engebretson F 2y

you can see from the children's ages that their mother has died, and Nettie was probably called upon to help, or had been originally hired to help, and a relationship happened. Ruth must be her own.

Back in time, 1885, here is Albert with his parents, and siblings.

https://familysearch.org/pal:/MM9.1.1/MQX4-X1F

Name: Albert Engebretson
Residence: Medo, Blue Earth, Minnesota
Age: 23 years
Estimated Birth Year: 1862
Birthplace: Iowa
Race: White
Gender: Male
Family Number: 52
Volume: Blue Earth
Page Number: 8
Film Number: 000565734
Household Gender Age
Ole Engebretson M 50y
Kari Engebretson F 53y
E M Engebretson M 25y
Albert Engebretson M 23y
Bessie Engebretson F 21y
Bernie Engebretson M 16y
Charles Engebretson M 13y
August Engebretson M 11y

Source Citation

Albert is born in Iowa, of Norwegian immigrant parents. Their oldest son was born in Iowa about 1860, and the younger kids born in Minnesota, so the family moved to Medo Township, Blue earth County sometime in there, probably homesteading.

Between Bessie born 1864 and Bernie born 1869, was their move.

Here is someone online who has purchased a photo of Albert's parents, Ole and Carrie Engebritson from Medo, Blue Earth, MN

http://forgottenoldphotos.blogspot.com/2012/03/photo-number-...

Other people have added to the Engebritson genealogy on the webpage.

Are you related to this family, or Nettie?