Chives (herb) is classed perennial in the cited extension guidance. The timing rules below are relative to your local freeze dates — enter a location to turn them into calendar dates.
The rules this site applies
Method
Frost-relative window
Rule & reconciliation
Start seeds indoors
8–6 weeks before the median last spring freeze
Wisconsin Horticulture starts chive seed indoors before the last frost date for planting out after frost danger, but says only 'a few weeks'; USU Extension fixes the lead time at 6 to 8 weeks of growth before garden planting, so sowing runs 8 to 6 weeks before the last spring freeze.
Transplant outdoors
from the median last spring freeze to 2 weeks after
UMN Extension says the easiest and most successful way to grow chives is planting rooted clumps in spring after frost danger has passed, and Wisconsin Horticulture likewise puts indoor-started plants out after the danger of frost is past; both agree, so the window opens at the last spring freeze.
Variety assumption: Wisconsin Horticulture warns that direct-seeded chives give little or no harvest the first year, so rooted clumps or indoor-started transplants are the practical route.
"Seeds can be started indoors a few weeks before the average date of last frost to be planted outside after the danger of frost is past, or can be direct seeded once the soil is warm."